SCOPE NEWSLETTER

NUMBER TWENTYPIVE DECEMBER 1997

AUSTRALIA p.2 ITALY p.S DARLING RIVER ALGAL BLOOMS ALTERNATING AEROBIC AND A three year project was carried out in the ANAEROBIC CONDITIONS TO Darling River at Bourke, the geographical INCREASE PHOSPHATE REMOVAL centre of the well-documented 1991 algal FROM W ASTEWATER bloom. The purpose was to study whether Traditional wastewater treatment plants do not nutrients or other factors were limiting algal exceed P efficiencies of 30%. The Phostrip, growth Bardenpho and A/0 processes, recently developed and implemented in sewage plants AUSTRALIA p.2 have substantially improved this P recovery. THE CATCHMENT MANAGEMENT This paper, focusing on A/0, describes the SUPPORT SYSTEM (CMSS) - A PILOT optimisation of this process in a laboratory­ STUDY IN THE MURRUMBIDGEE scaled single basin, by alternating sequences of CMSS, a decision support system, was aerobic and anaerobie phases. developed for the Murrumbidgee catchment, (81 948km2). The simple computer program NETHERLANDS p.6 needs neither a technical nor computing HIGH NUTRIENT REMO VAL IN THE background to set-up. This pilot study THREE-SLUDGE SEWAGE TREATMENT demonstrated the application of the system to a This three stage concept combines a high­ specifie area as an initial phase prior to its loaded activated sludge plant plus a settler for application to major catchments in New South the biological removal of P, with two biofilm Wales. reactors for nitrification and denitrification (by adding a carbon source). A pilot unit (2-3p.e.) IRELAND p.3 showed that sufficient residence time for PHOSPHORUS LOSS FROM SOIL TO bacteria activity was critical in P removal (to WATER lmg/1) but that N reactors were relatively flow This book, published following an insensitive. A patent is pending. international workshop, provides a valuable

reference resource on the state of knowledge of INTERNATIONAL p.7 both pathways and mechanisms associated with SECONDARY SETTLING TANKS phosphorus !osses from field and catchments. Over the last 25 years the adverse effect of wastewater discharges on the aquatic UNITED KINGDOM p.4 environment has led to stringent legislation PRECISION F ARMING FOR controlling treatment plant outputs. This FERTILISER APPLICATION POLICIES International Association on Water Quality This paper reviews the utilisation of fertilisers (IAWQ) report concentrates on improved in precision farming as part of an integrated activated sludge systems and the need to back management system. The distinguishing factor this treatment stage with a weil designed SST is the acknowledgement that significant thereby ensuring effluent quality under variability exists not only between fields but fluctuating influent quality and quantity also within them. conditions.

SCOPE NEWSLETTER produced by NEWTON CONSULTING NETWORK- 9, rue Newton - 75116 PARIS FRANCE -Tel. 33-1-53-97-7698 AUSTRALIA also divided into readily bioavailable DIN (dissolved inorganic nitrogen), the less DARLING RIVER ALGALBLOOMS assimilable organic nitrogen compounds, and particulate-bound N. The National Resource Management A Centre (NRMS) has recently finished a study of the readily bioavailable nutrients three year project in the Darling River at (DIN:FRP) showed that (as later confirmed in Bourke, the geographical centre of the a bioassays experiment in a field ail 6 well-documented 1991 algal bloom. The laboratory) samples tested suggested purpose was to study whether nutrients or nitrogen limitation. other factors were limiting algal growth. However, these methods do not determine The Vollenweider model, developed from possible limitation at the time of sampling. ln European and N.American research, was situ measurements to determine the initially used to study a series of weir pools instantaneous physiological response in the connected by short riverine stretches. It was algal cell to nutrient spike using Nutrient found that Chlorophyll-a concentrations v. Induced Fluorescence Transient ("NIFT") 8 total P loading did not match levels predicted assays showed that 2 of samples were by the model developed for deep lakes, and in nutrient limited and both of these a riverine context can only be considered as demonstrated N deficiency. The authors indicative. So, what is limiting algal growth conclude that these conditions can provide a in the Darling River? competitive advantage to cyanobacteria, which can fix atmospheric nitrogen and are This has led to the development of two not dependent on water-born DIN. hypotheses: In the case of the second hypothesis, it was • "algal growth is limited by nutrient availability ". found that turbidity at Bourke was clearly related to flow regime during the study • "the light climate in the Darling River is usually inadequate for algal photosynthesis and period (median turbidity 250 NTU). The hence light availability controls algal growth". analysis of the 2 longest "no water flow" periods since 1945 in '94 and '95 In the first hypothesis, TN:TP ratios were at demonstrated that it is a combination of first determined - sorne of the 8 samples were water column stratification and increased found to be N limited, whilst others were P light penetration due to decreased turbidity limited. that provides a dramatically improved light climate for algal photosynthesis. However, However, use of TN:TP ratios in Australian even if turbidity was normally less than 40 A. conditions is limited, as not all N or P is NTU during the large Circinalis bloom in bioavailable. Often a very small amount of 1991, it was found that extended periods of total P is in the nominally dissolved fraction low turbidity were not the only influencing ( < 0.003JLm). This is known as filterable factor in excessive algal growth for turbidities reactive phosphorus (FRP) and is assumed to have often been �40 NTU without the be the most readily bioavailable. Total N is development of large blooms.

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T o conclude, if there is indeed sufficient CMSS can thus be used to assess the impact bioavailable phosphorus in the Darling River of nutrient loading from changes in land use for an algal bloom to occur at any time, it is and management practices. The system stores the imbalance between the consumption of the quality of the information and can the FRP by the alg�e and the slow rate of its indicate any gaps in the information as weil resupply stemming from the sediments, that as reliability of outputs. actually limit eventual algal biomass. This re­ supply can be further retarded by Although data demands are minimal, manipulating nver flows to prevent collection of the data was time consuming stratification. due to the size of the area. 53 subcatchments, MR. Grace, Mraci, B. T.Hart, Fraci, R.L. Oliver each with 20-99 mapping units, were & C.M.Rees. Chemistry in Australia, August identified. Shortcomings included the 1997, Vol. 64, N°7,pp 2-5 absence of an instream nutrient assimilation component and nutrient bio-availability factors. AUSTRALIA CMSS includes a policy module - it accepts THE CATCHMENT MANAGEMENT and analyses land use and management SUPPORT SYSTEM (CMSS)- A PILOT "policy" statements. It also includes a STUDY IN THE MURRUMBIDGEE predictive model component involving a simple nutrient balance madel - thus it can CMSS, a decision support system, was calculate likely nutrient loads given a developed for the Murrumbidgee particular land use pattern and set of Catchment, an area of 81 948km2, within generation rates. the Murray Darling Basin. The simple computer program does not need a Land use data was extended to register point technical or computing background to set­ sources - sewage treatment plants, piggeries up. This pilot study demonstrated the and fish farms. application of the system to a specifie area as an initial phase prior to its application Nutrient loads were calculated using '93 to major catchments in New South Wales. conditions- 3 400±595 tonnes total P and 26 000±4 500 tonnes total N. Overall, average The area covers several large population total P and N generated is 0.4±0.1 kg ha-l - -1 centres and much of the intensive farming year·l and 3.2±0.5 kg ha l year involves irrigated agriculture. respectively. The land use contributions showed that 95% of nutrients are generated The system needs carefully collected and by diffuse source and only 5% by point accurate information. Four key sets of data sources. Dry land cropping, unimproved and are required: improved pasture generate 80% of all • land use data nutrient loads; sewage treatment plants • mapped land attributes generate only 4%. • expert assessment of nutrient generation rates • land use and land management practices.

3 These results highlight the need to focus on This publication should form the basis for certain parts of the catchment and consider the development of workable strategies for the use of buffer strips etc. to reduce diffuse controlling agricultural P !osses and reducing nutrient source inputs. CMSS has been or completely preventing this potential incorporated into the NSW Algal contribution to eutrophication. Management Strategy and implemented in H Tunney O. T.Carton, P.C.Brookes & A.E. many NSW catchments. The Murrumbidgee johnston. 468p., CAN International CMSS is now being revisited to prepare its Publishing, 1997, ISBN 0 85199 156 4. catchment nutrient management plan. S. Cuddy, B. Young, R.Davis & Trevor Farley. . Managing Algal Blooms, Ch.9, pp. 103-113, UNITED KINGDOM 1997 ISBN 0 643 060499. PRECISION FARMING FOR FERTILISER APPLICATION POLICIES IRE.LAND This paper reviews the utilisation of PHOSPHORUS LOSS FROM SOIL TO fertilisers in precision farming as part of WATER an integrated management system. Calculation of standard fertiliser This book, published following an recommendations for a particular crop is international workshop held at Teagasc, based on factors such as soil type, crop Wexford, Ireland in September 1995. It yield, fate of crop residue etc. Guidance is provides a valuable reference resource on given on a field by field basis. The the state of knowledge of both pathways distinguishing factor in precision farming and mechanisms associated with is the acknowledgement that significant phosphorus losses from field and variability exists not only between fields catchment. but also within them.

Participants from over 20 countries Precision farming has been made possible established a new and more detailed through the use of new technologies. understanding of the fate of P in agriculture Automated techniques, using soil sampling and its contribution to the aquatic load. and yield maps , have been developed There is a growing appreciation that sewage allowing only the necessary amount of works point source control alone will not fertiliser to be placed on the land,. A series of resolve the P input issue and that agriculture experiments has been used to establish has a major role to play. Diffuse farmland sampling procedures providing results with pathways and mechanisms were explored an acceptably low level of variance. and, where data was available, qualified and quantified. At such a level of precision critical levels of nutrients can be defined to limit runoff and In addition to an 18 chapter comprehensive leaching. review, 45 posters are presented in the tex:t. The Differentiai Global Positioning System (DGPS) is the US developed location system,

4 SCOPE NEWSLE_TIER __�- �-�--

adopted from the Global Positioning System ITALY (24 earth satellites) and used for precision farming. DGPS receivers can be mounted on ALTERNA TING AEROBIC AND harvesters, sprayers or spreaders, or used as ANAEROBie CONDITIONS TO hand held units and give positions in real INCREASE PHOSPHATE REMOVAL time. FROM WASTEWATER

Different types of fertiliser spreaders are Traditional wastewater treatment plants available. These already have the facility for do not exceed P efficiencies of 30%. The automatic rate control and severa! can be Phostrip, Bardenpho and A/ 0 processes, controlled by the combined use of a recently developed and implemented in predetermined application map/plan and the sewage plants have substantially improved GPS receiver. this P recovery. This paper, focusing on A/0, describes the optimisation of this The yield map is essential to a fertiliser plan process in a laboratory-scaled single basin, which needs to relate the real inputs of by alternating sequences of aerobic and phosphate, potash and magnesium to the anaerobie phases. quantities removed in the harvested crop. The key to precision farming is the Generally phosphorus is removed through generation of a within-the-field yield map. thickened sludge, with an efficiency of -30%. The remaining phosphorus is then removed The paper concludes that precision farming using chemical additives, thereby adding to relies on measurement and that the current costs. High phosphorus content in the sludge lack of collected reliable data, due to the makes it more suitable as fertiliser when degree of manual input required, is a major agricultural spreading is permitted. constraint. The development of suitable sensors will lead to the development of more In this study anaerobie conditions lasting 15h robust models for fertiliser were alternated with aerobic conditions of 9h In in recommendations. future, variation duration. A synthetic wastewater was used quality will become as important as variation following inoculation of an activated sludge in yield. Finally, environmental benefits will (enriched with Acinetobacter spp) from the ultimately play an important role but will municipal treatment plant in Puntavagno, need to be quantified in order to give the Genoa. needed impetus to this new technique. Fertiliser C.J.Dawson. The Society, Proceedings Results incorporated a residence time in N°391, December 1996 ISBN 0 85310 0241. arder to allow biomass to adapt to high phosphorus levels. The process studied reduced the start-up time from 30 to 20 days, stabilised removal yield to 90% and prevented wash-out of suspended solids. It was concluded that the biomass fraction, which was unable to adapt to high phosphorus levels, becomes progressively eliminated. Results of continuous

5 phosphorus removal runs at 4 different feed The pilot plant, for 2 to 3 p.e., was fed with phosphate concentrations (i.e. 18, 36, 68 & raw domestic sewage. The hydraulic load of 100mg/l) show that P-accumulating the plant was increased regularly and thus the rnicroflora are able to completely metabolise hydraulic residence time (HRT) decreased. phosphate as polyphosphate up to an Real-life conditions were duplicated. Both the influent phosphores concentration of influent and effluent of each bioreactor were -SOmg/1. For P influent > SOmg/1, continuously sampled and, twice a week, on phosphate removal yield eventually decreases every third and fourth day, composite up to 85%. Over 90mg/l the system tolerates samples were analysed. The experiment was phosphorus overload for no more than 10 divided into 2 periods, each of 14 weeks. days, after which the yield falls to zero. Increasing hydraulic 1oad, and thus The paper concludes that fixed and decreasing HR T decreased the removal operational costs appear substantially lower efficiency of the dephosphatating stage, due to the eliminationof the separate aerobic although removal efficiencies remained stable vessel and by lirniting aeration to only 40% in the second and third reactors. This implied of process time. that the first stage could be a limiting factor CSommariva, A. Converti & M.Del Borghi. in this new concept. Rej Desalination, 108, (1996} pp255-260. The required effluent standards for N total and P total were easily achieved (respectively NETHERLANDS 10mgN/1 and lmgP/1). It was surprising to note that the concentration of suspended HIGH NUTRIENT REMOV AL INTHE solids remained low (3mg/l), probably due to THREE-SLUDGE SEWAGE the filtration capacity of the carrier materials TREATMENT in the biofilm reactors. Total HRT was 10.4hrs, compared to 20hrs in conventional This three stage concept combined a high­ WWTPs. loaded activated sludge plant plus a settler for the biological removal of P, with two Rainfall and day/night effects led to dramatic biofilm reactors for nitrification and changes in the influent flow rate - during denitrification. A pilot unit (2-3p.e.) rainfall removal efficiency was satisfactory in showed that sufficient residence time for the first period (2.5 times dry-weather flow) bacteria activity was critical in P removal but in the second (3 times dry-weather flow) (to lmg/1) but that N reactors were it decreased with the final mean proceeding relatively flow insensitive. A patent is effluent concentration P-total at 1.8mg/l. pending. However, high concentrations of P input (up to 25mg/l) were removed to a level lower The aim of this research carried out at than 2mg/l after passing through the 3 Wageningen Agricultural University was to: reactors, even during rainfall. This proves the system's good removal capacities. The system • determine maximum hydraulic load also found to be very flexible since the • determine the effect of hydraulic peak loads was biomass easily recovered from peak loads. • evaluate economie prospects of the system

6 SCOPE NEWSLETTER

Investment costs are lower or comparable to scientists involved in the design and those of an ultra-low-loaded activated sludge operation of activated sludge WWTPs. plant. Operating costs are comparable and, moreover, this new technology could be a Activated sludge systems have been extended very interesting alternative if required space from organic carbon removal, to include N is considered ( only about a third of the size removal by nitrification and denitrification, of a conventional sytem for 100 000 p.e.). as weil as the removal of phosphates. The Costs of controlling odour problems were configuration of the system has, as a relatively low. consequence, increased in complexity and the number of physical, biological and chemical The next phase of the research is to scale up processes and substances influencing effluent the system to a semi-technical scale (500 p.e.), quality has expanded. focusing on removal efficiency and stability at full scale conditions. The final goal would The SST plays a major role in achieving the be fully-sized operating plant in the near increasingly demanding quality standards for future. ensuring the efficient "capture" of SS. At E.H.Marsman, P.].Roeleveld & J.HRensink many WWTPs, improvements in effluent

Ref. Wat. Sei. Tech. Vol. 35, N°10, pp129-136, COD (BODs), total N and total P can only 1997. be achieved by reducing effluent SS concentrations. This can often be INTERNATIONAL accomplished without the additional cost of effluent filtration through the simple SECONDARY SETTLING TANKS improvement of SST design and operation in (SSTs) THEORY, MODELLING, general and, in particular, by incorporating DESIGN AND OPERATION improved flocculation features. G.A.Ekama, J.L.Barnard, F. WGünthert, & Over the last 25 years the adverse effect of P.Krebs, f.A.McCorquodale, D.S.Parker wastewater discharges on the aquatic E.J. Wahlberg. Scientific Technical Report(STR) lA environment has led to stringent N°6, WQ, ISBN 1 900222 03 5, ISSN 1025- legislation controlling treatment plant 0913, 1997. outputs. This International Association on Water Quality (lAWQ) report concentrates on improved activated sludge systems and the need to back-this treatment stage with a weil designed SST thereby ensuring effluent quality under fluctuating influent quality and quantity conditions.

This up-to-date manual covers international developments in SST design, practice and research since the 1970's. The targeted audience are principally engineers and

7 The SCOPE Newsletter is produced by the CENTRE EUROPEEN D'ETUDES DES POLYPHOSPHA TES, the phosphate industry's research foundation and a sector.group of CEFIC (The European ChemicallndustryCouncil).

The SCOPE Newsletter seeks to promote a better understanding of the sustainable use of phosphate and the rôle of phosphate in the Environment

The SCOPE Newsletter is open to input from its readers and we welcome ali comments or information. Contributions from readers are invited on ali subjects concerning phosphates, detergents, sewage treatment and the environment. You are invited to submit scientific papers for resume or full publication, to send comments on the studies mentioned in this Newsletter or other scientific or technical views:

For more information, please contact : . NEWTON CONSULTING NETWORK.- who produce this SCOPE Newsletter- 9, rue Newton, Paris, France, Tel: 33-1-53-57-7698 Fax 33-1·53-57-7679 e-mail : [email protected]

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9 SCOPE NEWSLETTER

NUMBER TWENTY FOUR OCTOBER 1997

THE NETHERLANDS p.2 DENMARK p.S THE METABOUSM OF MICRO-ORGANISMS ALGAL BIOMASS REGULATION IN A SMALL RESPONSIBLE FOR PHOSPHORUS REMOV AL LOWLAND STREAM Micro-organisms, which are able to accumulate The role of invertebrate grazing, phosphorus phosphorus as polyphosphate inside the cell, are widely concentration and irradiance in the regulation of benthic used in enhanced biological phosphorus removal from algal biomass on stones (sorne of which were treated with wastewater. No pure culture, having the same insecticide) were studied in a 3 year field experiment in a characteristics, has yet been isolated. This paper shows small Danish lowland stream. that it is possible to use enrichment, as opposed to pure cultures, to understand, on a metabolic level, the complex GERMANY p.6 dynamic stoichiometric and kinetic microbial DAMMING OF THE DANUBE - EFFECTS ON mechanisms. BLACK SEA BIOGEOCHEMISTRY Although damming is known to affect riverbourne SWEDEN p.3 nutrient loads and their ecosystems, effects in open coastal HUMAN WASTE RECYCLING waters are less certain. ln this report long term water and Human urine alone contains over 80% of the nitrogen and nutrient data from the River Danube to the Black Sea is 60% of the phosphorus in household wastewater; presented. A decrease of two-thirds in the load of dissolved furthermore it has very low levels of heavy metals. This silicate in the river is revealed, with a corresponding shift report studies the practicalities of a urine collection system in phytoplank.ton species away from diatoms. in a Swedish eco-village in order to recycle the urine for agricultural purposes, as a fertiliser; thus human waste can become a resource rather than a pollutant. LONG TERM RECORDS IN LAKE MENDOTA Mean Secchi disk readings, covering the six seasonal UNITED K.INGDOM p.3 periods for a large part of this century, plus other data, EVALUATION OF METHODS USED TO were used to assess the effects of nutrients and herbivory DETERMINE TOP IN SOIL SOLUTIONS on water clarity in Lake Mendota, (3985ha, 25.3m max. Due to a growing awareness of the significance of depth).

· phosphorus transfer to water across soil boundaries, a simple, high quality method to monitor the movement of FINLAND p.7 total dissolved phosphorus (TDP) is necessary. Analysis EFFICIENCY OF PHOSPHATE AND ZEOUTE can be problematic due to trace concentrations of P in the BASED WASHING POWDERS presence of higher concentrations of a number of organic This study was undertaken to determine if phosphate and and colloïdal fractions This paper evaluates a number of zeolite based detergent powders with differing physical methods used to determine TDP using leachate water properties were equally efficient at removing dirt under from lysimeters with 10 different UK soil types. A final similar washingconditions. recommendation is made. SCOTLAND p.8 AUSTRALIA p.4 PROCEEDINGS FROM EDINBURGH THE FILTER TECHNIQUE FOR SEWAGE CONFERENCE EFFLUENT TREATMENT - PART 2 The 1995 Edinburgh Conference, organized by the This report covers the planned trial application of the Scottish Environment Protection Agency, brought FILTER (Filtration & Irrigated cropping for Land together agriculturists, scientific advisors, water pollution Treatment & Effluent Reuse) technique in the Murray scientists and focused on issues relating to diffuse pollution River Basin - first referred to in Newsletter 20. A 16 from agriculture.- nitrates, phosphorus, pesticides plus the hectare pilot trial area is being leveled into irrigation hays nature and effectiveness of the regulatory regime. A to receive effluent from the Griffith Sewage Works. collection of the pa pers presented has been published. vital indicator as to why the 'real' phosphorus THE METABOLISM OF MICRO-ORGANISMS removal organism has never been enriched. RESPONSIBLE FOR PHOSPHORUS A metabolic model able to describe conversion rates REMOVAL of all components involved in the process was developed. The main difference between oxygen and nitrate as an electron acceptor is the different efficiency of oxidative phosphorylation. The Micro-organisms, which are able to accumulate parameters necessary in a metabolic model are fewer phosphorus as polyphosphate inside the cell, are than for a black box model. Model predictions were widely used in enhanced biological phosphorus coherent with experimental results and mass removal from wastewater; the competitive balances over each experiment were closed, advantage being their ability to use indicating that all components of the process are polyphosphate as an energy source for the uptake known and that the metabolism of the organisms and storage of acetic acid. No pure culture, could be described in terms of stoichiometrics and having these characteristics, has yet been isolated. kinetics. This paper shows that it is possible to use enrichment, as opposed to pure cultures, to Storage polymers play an important role in natural understand, on a metabolic level, the complex ecosystems, which rarely have constant supplies of dynamic stoichiometric and kinetic microbial electron acceptors. There is a need to develop these mechanisms. dynamic selective enrichment techniques in the context of both microbial ecology and new The difficulty in obtaining a pure culture is due to processes in environmental biotechnology. For the fact that enrichment procedures used are static. instance, substrate accumulation by micro-organisms The organisms involved have a strong competitive of organic compounds from dilute waste flows could advantage due to their ability to adapt to highly allow for these compounds to be reused ( eg : dynamic conditions. The theory, based around methane gas digestion). Phosphate Accumulating Organisms (PAO), was M CM. Van Loosdrecht, G.JSmolders, T.Kuba & sufficient to empirically design and operate processes JJHeijnen. Ref.: Antonie van Leeuwenhoek 71: 109· - but lack of knowledge means trial and error 116, 1997. procedures are used in process designs, and causes of disturbance are difficult to detect. No pure culture has yet been reported to have the full range of characteristics equivalent to the behaviour of polyphosphate organisms in activated sludge. HUMAN WASTE RECYCLING

Cultures enriched in the laboratory were used in the 80% most successful studies. Sludge is exposed to Human urine alone contains over of the 60% anaerobie and aerobic conditions in sequencing nitrogen and of the phosphorus in batch reactors (SBR), with acetic acid only present household wastewater; furthermore it bas very during anaerobie periods thereby allowing growth low levels of heavy metals. This report studies the of only those organisms capable of metabolising practicalities of a urine collection system in a acetate in the absence of electron acceptors. Swedish eco-village in order to recycle the urine to agriculture as a fertiliser; thus human waste Stoichiometric coupling between ortho-phosphate can become a resource rather than a pollutant. release and acetate uptake under anaerobie conditions was noted in early studies. The organisms The toilets used were equipped with two bowls, for do not accumulate phosphate when substrate and the separate collection of urine and faecal material, electron acceptors are present - this could be the and with two separate flushing systems, requiring only a small volume of water to be flushed. The

2 SCOPE NEWSLETTER

urine was piped to a collection tank, followed by a storage tank where it was sanitised and consequently EVALUATION OF METHODS USED TO DETERMINE TOP IN SOIL SOLUTIONS used as fertiliser for cereal crops. The source separation of urine can be added to any sewage system. Due to a growing awareness of the significance of phosphorus transfer to water across soil The purpose of the study was to measure the boundaries, a simple, high quality method to quantities of nutrients per person, daily, separated monitor the movement of total dissolved into the urine fraction, as weil as the collection of phosphorus (TOP) is necessary. Analysis can be heavy metals and faecal contamination in the problematic due to trace concentrations of P in collection system. The urine solution was analysed the presence of higher concentrations of a chemically each time to study how rapidly the urea number of organic and colloïdal fractions. This dissociated to ammonium and carbon dioxide. The paper evaluates a number of methods used to experiment was carried out in Understen eco-village determine TOP using leachate water from on 44 apartments, 160 persons, during two lysimeters with 10 different UK soil types. A final consecutive 14 day periods. Each inhabitant filled in recommendation is made. a form relating collection of urine, heavy metals and nutrients to the amount of time they spent at home The study focused on the determination of TDP, (average 13.9 hrs per day). They were also asked if passing through the 0.45 p.m filter, including they were vegetarians (10%). The proportion of inorganic, organic and P attached to colloïdal children (2-13 yr.) in this study was higher than in material. This determination allowed the difference Sweden as a whole. between TDP and molybdate reactive P (MRP) to quantify dissolved, unreactive P in its various forms. All factors considered, quantities of nutrients were Dissolved P in soil solution may also be important, close to those expected, indicating that 80-100% of contributing to eutrophication if mobilised to the urine generated was correctly separated.. surface waters. Dissociation of urea in the collection pipes was rapid, activated by the biofilm layer lining the pipes. Soil was collected 7 days prior to analysis, from free­ A high proportion of nitrogen in urine is stored in draining lysimeters at experimental sites, covering a the form of ammonium/ammonia and the pH-value, (9) range of different soil types, notably at: Great Dun due to dissociation was high - thus ventilation of Fell, Aber and North Wyke. Three methods were the tank and collection pipes should be restricted to employed which used different digests with standard avoid ammonia emissions and losses. The urine molybdate blue colorimetrie determination: mild contained _3.2 mg cadmium/kg phosphorus, a very digestion (persulfate), peroxide-Kjeldahl and nitric low level compared to chemical fertilisers C26 mg sulphuric acid. In a fourth method inductively Cd/kg P) and sewage sludge (NSS mg Cd/kg P). coupled plasma-optical emission spectrometry (ICP­ Contamination with faecal material was low C 1mg OES) was utilised. Aqueous solutions were prepared faecal material/1 urine solution) and flush water containing nominal concentrations (100 mg PL-1), usage was diminished by 50 %. Source urine was and cooled to 4°C. On the day of analysis samples thus considered to compare favourably with mineral were prepared by 1000 fold to obtain a nominal fertilisers and other organic fertilisers of urban concentration of 100 p.g PL-1. Each of the soil and origin (eg. compost). synthetic solutions were replicated (n=S). H]onsson, T.A.Stenstrom, ].Svensson and A.Sundin. Ref Wat. Sei. Tech. Vo/.35, N 9 pp, 145-152, 1997. ° Soil solution concentrations of TDP were significantly different (P< 0.001) between methods. Eight of the ten soils contained MRP concentrations below 100 p.g L-1p_ AQUACHECK

3 {an interlaboratory sample exchange scheme) samples showed that data obtained by the ICP-OES THE FILTER TECHNIQUE FOR SEWAGE method and persulfate methods were the most EFFLUENT TREATMENT- PART 2 precise {%rsd=3%) but ICP-OES was not sensitive enough to use below 100 J.'g L-1 P· This report covers the planned trial application of The nitric acid-sulphuric acid digestion method was the FIL TER (Filtration & Irrigated cropping for slow and required constant attention. Recoveries for Land T reatment & Effluent Reuse) technique in model compounds were erratic; soi! solution was the Murray River Basin in Australia - first subject to high blank values and cross­ referred to in Newsletter 20. A 16 hectare pilot contamination; poor reproducibility at trace trial area is being leveled into irrigation hays to concentrations was also a problem. These receive effluent from the Griffith Sewage Works. disadvantages highlighted the need for an alternative procedure for routine analysis. The system was designed to reach EP A treated effluent targets by reducing phosphorus from 2-8 In the peroxide-sulphuric acid digestion experiment mgs/L to less than 1mg/L and nitrogen from AQUACHECK samples indicated that the method 20mg/L to less than 15mg/L by 1999 in a was not completely effective in recovering P. sustainable, efficient way. Although systems using Overall the method was considered to be reasonably artificial wetlands, cropping and woodlots are robust, although it was difficult to control the final gaining popularity, they are expensive in large urban stages to avoid superheating and volatilisation. centres, due to costs involved in storing excess effluent during periods when crop and pasture The persulphate digestion procedure, using sealed growth is low. In addition, on slowly permeable reaction vessels, was the mildest wet oxidation soils, such as those in Eastern Australia, method evaluated. Advantages included control waterlogging and salinisation often occur. simplification plus reduced contamination compared with other methods, which use open vessels. The A system was proposed whereby crops are grown acidified · conditions are less oxidising than the over a network of sub-surface drains, thus alkaline alternative, thus potential oxidation and combining irrigated cropping with filtration of 2 + interference from Mn are avoided. effluent through the soi! to a drainage system when cropping activity is low. The rate of sub-surface T o summarize, the most important factors in drainage could be regulated, ensuring sufficient obtaining accurate ·and precise estimates of TDP nutrient removal and reaching target criteria. were the sensitivity of the procedure, simplicity of oxidation conditions, plus the ability to control the Trials took place in 1994 (for details refer to reaction, thus avoiding contamination. On this basis Newsletter 20). Mean P concentrations feil by 98% the persulfate digestion method was recommended. to > O.Smg/L and N by 85% to > Smg/L. The A.P.Rowland & P.MHaygarth. jour. Environ. Quai. applied effluent contained blue-green algae Vol. 26, N°2 pp.410-415, March-Apri/1997. (Mycrocystis), whilst drainage waters were colourless and free of blue-green algae due to the increase in N:P ratio (as N:P falls below 12 so the risk of blue-green algae increases). Occurrence of downstream blooms was much less likely.

Other trials indicate the potential usage of the system to dean pesticide-contaminated run-off. Adapted versions of the system could be used to treat industrial and commercial effluent containing

4 SCOPE NEWSLETTER

chemicals and heavy metals, or management of found to be regulated by invertebrate grazing. It was salinity problems in irrigation regions. found that invertebrate scrapers could regulate algal biomass accretion and suggested that A.jluviatilis Encouraged by the success of the trials to date, a was largely responsible for invertebrate grazing year-long commercial scale trial is planned. The pilot pressure. The density of this snail on untreated system will cover 16 ha of farmland, and, if stones and stones treated with insecticide varied by successful, will be extended to 130 ha. This would be 50 %. Algo-biomass increased significantly on the sufficient to handle Griffith's (18 000 pop) sewage insecticide-treated stones. effluent in time to meet the EPA's 1999 deadline, whilst generating 1000T /yr of high quality grain and The phosphorus enrichment experiment was hay. conducted over 35 days in spring '91: an inorganic B. Bennett. Ref.:Ecos, Winter 1997, pp 30-33. phosphorus solution, from a butt on the bank, was continuously added to 3 troughs, whilst 3 others served as controls. Algal biomass development on stones was not found to be phosphorus limited ALGAL BIOMASS REGULATION IN A during the spring algal bloom, and th us could not be SMALL LOWLANDS� controlled by nutrient limitation.

The irradiance experiment was carried out over 70 The role of invertebrate grazing, phosphorus days in summer '91: two reaches, one shaded and concentration and irradiance in the regulation of one not, were used, and stocked with non-colonised benthic algal biomass on stones (sorne of which stones; 10 from each reach were sampled biweekly were treated with insecticide) were studied in a to monitor algal biomass and scraper density. A very three year field experiment in a small Danish low biomass accumulation occurred in the shaded -2 lowland stream: Gelbaek stream in Jutland. Three reach, whilst a peak of 800mg chlorophyll m experiments were carried out between March and occurred after 6 weeks in the non-shaded reach. August. It was concluded that invertebrate grazing can Inter-annual differences in peak-algal biomass were prevent significant increases in algal biomass despite presumed to be due to differences in grazing a surplus supply of nutrients. Reduced light pressure, with growth being further limited by a conditions, either from an overhead canopy or self reduction in light from leaf vegetation proliferation shading, also play a part in limiting algal biomass on the banks in the summer. Three experiments increase. Insecticides, it was shawn, may have the were designed to determine: reverse effect of permitting algal growth due to reduced grazing input. Algal biomass regulation can • if invertebrate grazing in early spring could be considered as a complex interaction of top-down regulate algal biomass development and bottom-up mechanisms. • if algal growth was phosphorus limited in spring K.Kjeldsen Ref.:Freshwater Biolog;y (1996} 36, 535-546. • if a fall in light due to leaf proliferation could limit algal growth thus determining the timing of peak biomass.

The invertebrate grazing experiment, conducted over 44 days in spring '92, used an aluminium frame, consisting of 4 troughs stocked with stones originating 20m upstream. Stones from two of the troughs were treated with an insecticide (Permethin). Nutrient concentrations were high (orthophosphate 33-117JLgl-1). Algal biomass was

5 silicate inputs, overfishing plus the introduction of DAMMING OF THE DANUBE- EFFECTS ON alien species, have yet to be studied. BLACK SEA BIOGEOCHEMISTRY Similar dam constructions world-wide (more than 36 000) should now be examined for their possible Although damming is known to affect influence on food web structure in closed seas, lakes riverbourne nutrient loads and their ecosystems, and rivers since these effects could be of global effects in open coastal waters are less certain. In consequence. this report long term water and nutrient data C.Humborg, V.Ittekkot, A. Cociasu & B. V.Bodungen. from the River Danube to the Black Sea is Ref.: Nature, Vol. 386, 27 March 1997, pp. 385-388. presented. A decrease of two-thirds in the load of dissolved silicate in the river, was revealed, with a corresponding shift in phytoplankton species LONG TERM RECORDS IN LAKE away from diatoms, since dam constructions in MENDOTA the early '70s. Results show that the biogeochemistry of the entire Black Sea basin bas been altered. Mean Secchi disk readings, covering the six seasonal periods for a large part of this century, Dams can reduce nutrient loads due to the removal plus other data, were used to assess the effects of of nutrients to reservoir sediments ('the anificial­ nutrients and herbivory on water darity in Lake lake effect' ) . Although this removal could be Mendota, Wisconsin, (3985 ha, 25.3 m max. compensated for by anthropogenic nitrogen and depth). phosphorus inputs downstream, no such compensation has been observed for silicate. Median The control of phytoplankton blooms and the role silicate concentration (58�-LM) in the Danube for the nutrients and zooplankton play is not fully period 1979-92 is considerably lower than for the understood. This study seeks to understand if, in the pre-construction period 1959- 60 (1401-LM). In winter, long term, grazing can improve water clarity in a concentrations of silicate in coastal waters 1960-92 large eutrophie lake, at varying nutrient levels. The fell from 55�-LM to 20�-LM, after the dam was built. lake has a history of algal blooms since at least the Nutrient concentrations on the coast were also late 1800s. It has been subject to increased influenced by the Danube - though nitrogen and phosphorus loading rates during this century. phosphorus were only slightly affected by coastal sources. The dramatic fall in the Si:N ratio (42 to Readings were divided into 6 seasonal periods 2.8) can be accounted for by the increase in dissolved distinguished by a number of precisely defined organic nitrogen from increased inputs from the criteria. It was found that despite different nutrient­ Danube. This change in nutrient inputs has led to a herbivory interactions the summer algal blooms had dramatic shift away from diatoms to not increased since 1900. Water clarity was at its coccolithophores and flagellates (non-silica based): greatest from spring turnover through to autumn increases of a factor of 2.5 and 6 were noted destratification, corresponding to the time when respectively. It can be assumed that a large part of herbivory levels were high. Indications are that lake the increase in nitrogen loads after damming of the size and trophic status do not prevent lakes from Danube are being, and will be, removed by non­ achieving increased water clarity from diatom species. The effect of the decrease in silica biomanipulation that increases herbivory. Grazer was also observed in the Black Sea. effects on water clarity can be seen over a long period, and, in principle, there may be no time The occurrence of taxie flagellate blooms may restriction on grazers' capacity to control become more widespread - to the central Black Sea - phytoplankton. In practical terms, however, as observed in other coastal areas. Effects of altered sustained biomanipulation may be problematic. The

6 SCOPE NEWSLETTER

authors conclude that management programmes P involving reduction and biomanipulation may be PROCEEDINGS FROM EDINBURGH more effective than if only one technique is used on CONFERENCE its own. R. C.Lathrop, S.R. Carpenter and L. G.Rudstram. Ref.: Can.]. Fish. Aquat. Sei 53:2250-2261. 1996. The 1995 Edinburgh Conference, "Diffuse Pollution and Agriculture", organised by the Scottish Environment Protection Agency, EFFICIENCY OF PHOSPHATE AND brought together agriculturists, scientific ZEOLITE BASED W ASHING POWDERS advisors, water pollution scientists and focused on issues relating to diffuse pollution from agriculture - nitrates, phosphorus, pesticides plus This study was undertaken to determine if the nature and effectiveness of the regulatory phosphate and zeolite based detergent powders regime. A collection of the papers presented has with differing physical properties were equally now been published. efficient at removing dirt under similar washing conditions. These conference papers provide an up-to-date account, and a perceptive insight, into a growmg Results were correlated in terms of whiteness, environmental problem in agriculture. redness and blueness, as well as detergent residues in the materials and the washing machines. The presentation of the papers led to a good debate and the establishment of a strong rapport amongst Smaller particle zeolites-based detergents did not participants. Emphasis was on future actions and it wash as well as larger particle detergents and the was agreed that research into practical solutions, co­ former lefi: more residue. New clothes with coarse operation at all levels and the formation of fibres had the most residues. partnerships were the only way to bring about lasting change and improvement. Evidence of strong It was found that phosphate based detergents lefi: commitment to the debate has been witnessed since, significantly less residue and increasing the number through both follow-up research on nitrates, and the of washes did not have any effect on the amount of establishment of partnerships aimed at the phosphate residues lefi:. This discrepancy was all the application of new farming methods. more apparent when energy saving washing machines using less water and mechanical input were A follow-up regional conference is planned in 1997 used. ensuring that the original impact of this first conference was sustained. Residues imply possible irritation and sensitivity for Edited by T.Petchey, B.D �rey and A.Frost, The the user, which could be minimised by using ScottishAgricultural College, 1996, ISBN 1 85482 phosphate-based detergent powders. 575 5. HAino. Ref.: Master's Thesis, University of Helsinki, Faculty ofAgri culture and Forestry,May 1997.

7 The SCOPE Newsletter is produced by the CENTRE EUROPEEN D'ETUDES DES POLYPHOSPHATES, the phosphate industry's research association and a sector group of CEFIC (The European Chemical Industry Council).

The SCOPE Newsletter seeks to promote a better understanding of the sustainable use of phosphate and the role of phosphate in the Environment

The SCOPE Newsletter is open to input from its readers and we welcome ali comments or information. Contributions from readers are invited on ali subjects concerning phosphates, detergents, sewage treatment and the environment. Y ou are invited to submit scientific papers for resume or full publication, to send comments on the studies mentioned in this Newsletter or other scientific or technical views:

For more information, please contact : NEWTON CONSULTING NETWORK- who produce this SCOPE Newsletter- 9, rue Newton, Paris, France, Tel : 33-1-53-57-7698 Fax 33-1-53-57-7679 e-mail : [email protected]

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8 SCOPE NEWSLETTER

NUMBER TWENTY THREE SEPTEMBER 1997

THE NETHERLANDS p.2 FRANCE p.4

SELECTIVE REMOVAL AND RECOVERY OF DIFFERING EUTROPHICATION GRADIENTS IN PHOSPHATE USING A NEW CLASS OF SORBENTS­ COAST AL LAGOONS II- PROCESS OPTIMISATION Eutrophication conditions are described in three lagoon The main processes conceming the precipitation of calcium systems, differing in structure, catchment and connection phosphate in a fluidized bed were established (see Newsletter with the sea: the Bassin d'Arcachon on the Atlantic coast, 22). An optimisation of the phosphate removal efficiency SW France, the semi-artificial fish ponds of the Bassin was attempted, in this second paper, by focusing on the d'Arcachon and the Etang du Prévost on the Mediterranean aggregation process. coast.

AUSTRIA THE NETHERLANDS p.2 p.S

ENVIRONMENTAL IMPACTS OF NUTRIENT PHYSIOLOGICAL ADAPTATION PROCESSES TO REMO VAL PROCESSES CHANGES IN THE ENVIRONMENT The influence of primary clarification of sewage on nitrogen The properties of the phosphate uptake system of the and phosphorus removal was studied, in a modified cyanobacterium Anacystis nidulans were studied during the University of Cape Town type wastewater treatment plant transition from a phosphate-deficient non-growing state to a (WWTP), using batch tests, on a full scale, before and after non-deficient growing state. The paper is a detailed scientific the introduction of raw sewage. Both the effect on the study of the various physiological adaptation processes by activated sludge population and the overall environmental which organisms react to changes in their environment. impacts were studied. POLAN D p.6 THE NETHERLANDS p.3 SUBSTITUTION OF POLYPHOSPHATES IN EFFECTS OF ANIMAL W ASTE APPLICATION TO POPULAR POLISH DETERGENTS SANDY SOILS ON DOP LEACHING This paper describes the possible impact of certain A substantial part of total Pin soil solution and leachates can substitutes of polyphosphates (NTA, EDT A) in detergents, exist as dissolved organic phosphorus (DOP), which may be on the environment. EDTA is reported as non­ more mobile than inorganic orthophosphate and so be an biodegradable, this, coupled with a high chelating capacity important P source for surface water. eutrophication. The may cause mobilisation of heavy metals from sediments. analysis of DOP has not been included in many field studies, NT A is essentially biodegradable though there is evidence of nor included in models developed to predict the movement non-biodegradable complex carry over. of P through the soil. This paper focuses on four experiments to investigate the effects of pig waste application to sandy UNITED KINGDOM p.7 soil on DOP leaching. CLEANING UP THE THAMES ESTUARY

INDIA p.4 A 69 page report "The Water Quality of the Tidal Thames", published by the Environmental Agency covers in detail the RECLAMATION OF EUTROPHIC WATERS: recovery of the Thames Estuary, from a heavily polluted NUTRIENT REMOVAL BY WATERHY ACINTH catchment to one of the cleanest metropolitan estuaries in the A vast number of tropical pond wetlands are no longer world. No phosphate restrictions were required. suitable for fish culture in India. Sophisticated ecotechnological models used for control of eutrophication j PLUS ... p.7 , in advanced countries are not suitable in the small, shallow ponds used for fishfarming in developing countries. The use THE PHOSPHATE FILE : of biological agents is ecologically significant due to their An informative booklet covering phosphate source, use and ease of handling and as component members they may cause fate in the environment. Jess perturbation. Nutrient removal capacity of waterhyacinth was studied.

SCOPE NEWSLETIER produced by NEWTON CONSULTING NETWORK- 9, rue Newton- 75116 PARIS FRANCE- Tel. 33-1-53-97-7698 Î

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By spreading the base dosage between at least two additional points a non-negligible supersaturation is SELECTIVE REMO V AL AND RECOVERY OF sustained for a longer period of time, improving PHOSPHATE USING A NEW CLASS OF phosphate removal efficiency by increasing both net SORBENTS- II- PROCESS OPTIMISATION. aggregation and molecular growth. Deviations in the model predictions were thought to be due to the contribution of the inlet stream kinetic energy to the

The main processes concerning the precipitation of total energy dissipation rate, suggesting that a high calcium phosphate in a fluidized bed were energy dissipation rate is detrimental to phosphate established (see Newsletter 22). It was suggested removal. that an improvement in the phosphate removal efficiency from 60% to 80% may be achieved if In conclusion, optimisation was achieved by selecting 3 process conditions are found favouring aggregation, sand grains of small sizes (0.1-0. mm), a low -3 molecular growth, or preferably both. Thus an superficial velocity (7xl0 mfs) and by spreading the optimisation of the phosphate removal efficiency base addition over two locations. The highest was attempted, in this second paper, by focusing on phosphate removal efficiency was found to be 0.8 for a the aggregation process. conversion of 0.25 after the first base dosage. The phosphate removal efficiency can be further improved

Experiments with a fluidized bed preceded by a pre­ by lowering the mixing intensity at the bottom of the mixing reactor as weil as without pre-mixing were reactor. Wat. Res. Vo/.30. W7 carried out. pp.J589-1596, 1996. M.M.Seck/er, M.JL. Van Leeuwen, O.S.L.Bruinsma and G.M. Van Rosmalen. In the first case the aggregation of the fmes with the grains in a fluidized bed was studied. A set-up was designed to isolate the aggregation from other processes and mathernatically modeled to take into account two competing mechanisrns: orthokinetic ENVIRONMENTAL IMPACTS OF NUTRIENT aggregation and breakage. In the second case (i.e. REMO VAL PROCESSES normal operation of a fluidized bed) experiments with a spread type dosage were also performed. Both experiments are described in the paper. In the fluidized The influence of primary clarification of sewage on bed preceded by a pre-mixing reactor it was found that nitrogen and phosphorus removal in a modified the aggregation model gives a fairly accurate University of Cape Town type wastewater prediction of the measured efficiency for both types of treatment plant (WWTP) was studied, using batch grains (fine and coarse sand) over the complete range tests, on a full scale before and after the of the total flow despite the spread in experimental introduction of raw sewage. The effect on the data, it also showed that small grains and a low activated sludge population and the overall throughput favour a high aggregation efficiency. environmental impacts were studied. ln the fluidized bed with the base dosage at the bottom, A WWTP in Holten, The Netherlands, is designed as a reactants were mixed with NaOH dosage and a high modified University of Cape Town type treatment local supersaturation was obtained. Predicted plant, operated with presettled sewage. The prirnary efficiencies were too low suggesting processes other sludge (including precipitated phosphorus) and the than aggregation. Most of the phosphate removal secondary sludge is digested. The treatment plant occurred at the bottom of the bed. Phosphate removal consists of anaerobie, anoxie, and aerobic zones, and efficiencies due to aggregation were equal to - 60% primary and secondary clarifiers. Presettled wastewater and to molecular growth of- 40%. is introduced into the anaerobie zone. Retum sludge from the secondary clarifier is recirculated to the start of the anoxie zone. Mixed liquor in the anoxie zone is

2 SCOPE NEWSLETTER

recirculated to the start of the anaerobie zone. The WWTP is operated at a long sludge retention time THE EFFECTS OF ANIMAL W ASTE (SRT) of 45 days, and the foilowing batch tests were APPLICATION TO SANDY SOILS ON DOP carried out: LEACHING

• Anaerobie phosphorus release tests

• Aerobic phosphorus uptake tests

• Anoxie phosphorus uptake tests A substantial part of total P in soil solution and • Anoxie phosphorus release tests Ieachates can exist as dissolved organic phosphorus (DOP), which may be more mobile than inorganic Before the introduction of raw sewage the maximum orthophosphate and so be an important P source released phosphorus was approx. 30 mg P/g volatile for surface water eutrophication. The analysis of suspended solids (VSS): this figure feil to 14 mg P/g DOP has not been included in many field studies, VSS after the introduction. The proportion of nor included in models developed to predict the phosphorus-removing organisms in total biomass movement of P through the soil. This paper focuses decreased from approx. 30-50% to 15-20%. Before on four experiments to investigate the effects of pig and after the introduction of the raw sewage the waste application to �andy soil on DOP leaching. contribution of denitrifying dephosphatation was similar, approx. 40-45% of total activity - indicating • Exp. 1 examined the effect of storing pig slurry on that denitrifying dephosphatation still contributed DOP fractionation using gel permeation significantly to phosphorus removal after the chromatography. introduction. The phosphorus release rate was, • Exp. 2 & 3 studied immediate and long term effects however, much lower under anoxie conditions than of animal waste application to soil in both laboratory under anaerobie conditions. The nitrification columns and outdoor maize-grown lysimeters (four efficiency feil from 84% to 73%, probably due to a treatrnents in triplicate for 7 yr.). decrease of SRT. Less nitrate was formed in the • Exp. 4 examined concentrations of DOP and total P effluent, although the nitrogen balance indicated that (TP) in soil solutions at various depths in a long term the improvement was due to extra nitrogen field experiment, between 1971 and 1982. assimilation because of extra sludge production. Net energy consumption rose (+75%) mainly because of The foilowing hypotheses were tested: the sludge handling but also in view of the decrease 1.DOP is a significant fraction of TP in leachates and (-45%) in methane production in the digester. -- in the soil solution, and this fraction increases with increasing soil depth. It is questionable whether the improved effluent 2. DOP is a larger fraction of TP in soils heavily qua1ity imposed by governrnent regulations obtained supplied with slurry than soils only receiving mineral by changing to raw sewage feeding had an overail fertilisers. positive effect on the environment. This work shows that evaluating treatment processes only on effluent A large amount of molybdate reactive P (MRP) was quality can lead to overail adverse effects on the found in high molecular weight (MW) material from environment. pig slurry liquid. The MRP probably originated from Journal of Environmental Engineering Vol. 13, N°l, acid hydrolysis during the analysis. This can cause an Jan. 1997 pp 33-40. MC.M. Van Loosdrecht, T.Kuba, underestimation ofDOP content in fresh pig slurry. H.M Vn Veldhuizen, F.A.Brandse, J.J.Heijnen.

In a manured sandy soil column more than 90% of P leached was present in the organic form. Results of the field experiment showed that DOP fraction makes up the largest part of TP in soil solutions below 50cm depth. Thus the first hypothesis was found to be correct. However the second hypothesis was rejected.

3 SUBSTITUTION OF POL YPHOSPHATES IN advertised as "phosphate free" contained 2.55g/kg of POPULAR POLISH DETERGENTS - phosphates in the orthophosphate form and high levels ENVIRONMENTAL IMPLICATIONS of EDTA. EDTA was found in the raw sewage - the level did not decrease as it passed through the treatrnent plant.

This paper describes the possible impact of certain substitutes of polyphosphates (NT A, EDT A) in EDTA is a strong complexing agent for divalent and popular Polish detergents on the environment. polyvalent metals. In Poland, industrial wastewater is EDTA is reported as non-biodegradable - this often rnixed with municipal wastewater after primary coupled with a high chelating capacity may cause pre-treatrnent. Naturally heavy metals forming strong mobilisation of heavy metals from sediments. NTA complexes with EDTA ligands are found at low concentrations. Higher concentrations of Ca and Mg is essentially biodegradable though there is evidence of non-biodegradable complex carry over. may occur but Ca-EDTA and Mg-EDTA have stability constants a few orders of magnitude lower.

The contribution of phosphorus from detergents to total phosphorus load in wastewater is approx. 30- The paper concludes that "phosphate free" (i.e. free 50%. Substitutes are proposed by the producers of from polyphosphate but not from inorganic commercial washing powders/liquid detergents: i.e. phosphorus) detergents are not neutral for the zeolites and organic chelating ligands environment. Stable chelating ligands may cause ethylenediaminetetraacetic acid (EDTA) and mobilisation of heavy metals from sediments. To nitrylotriamineacetic acid (NTA). Studies show that prevent unexpected effects in the water environment, none of them are as efficient as tripolyphosphates, nor limitations of non-degradable chelates is necessary. are they neutra! for the environment. The EDTA/NTA complex interaction with heavy metals in soil and water environments merits further

Levels of EDTA and NTA in raw domestic sewage careful study. 2 were measured at each step of the treatrnent process in Chemistry for the Protection of the Environment Hajd6w (near Lublin) in Poland inl994. The contents edited by Pawlowski et al, Plenum Press, New York, /996. & of EDTA and NT A in popular washing powders and M.R.Dudzinska A.Montusiewicz. liquid washing-up detergents (both Polish and imported) were verified. Hajd6w is a mechanical­ biological treatrnent plant, with no chemical stage, typical of municipal sewage treatrnent plants in CLEANING UP THE THAMES ESTUARY Poland. lt caters for the Lublin (400 000 inhabitants) and Swidnik (20 000 inhabitants) communities. A 69 page report entitled "The Water Quality of Studies show that no polyphosphates are found in the the Tidal Thames" bas been published by the raw sewage thus only data for EDTA and NT A was Environment Agency. It covers in detail the presented. NTA was not found in the raw sewage recovery of the Thames Estuary, from a heavily although the most common powder and the least polluted catchment to one of the cleanest common (due to its high priee) concentrate powder metropolitan estuaries in the world. No phosphate contain large amounts of NT A. Waste from industry restrictions were required to manage the 14 000 2 may dilute the stream at the entrance to the plant so km area with 12 million population. NT A was not detected. Results for EDTA were very different : almost ali washing-up liquids contained The recovery was achieved by the restoration of water EDTA, except a liquid produced in Western Europe, quality. The most important factor in water quality advertised as "environmentally friendly". Results for control in the Thames is dissolved oxygen and powders varied, the concentrate powder contained improved sewage treatrnent standards, particularly highest levels of phosphates and chelates and was the under summer conditions in order to ensure adequate only product containing EDTA and NTA. The powder oxygen reserves i.e. 30% saturation..

6 SCOPE NEWSLETTER

Eutrophication was not considered to be a problem in Analysing the interactions between phosphates and the main body of the estuary due to strong tidal flows, water quality, the « Phosphate-File » lays out the need salinity variations and high turbidity, precluding the for improved sewage recovery as a means not only to development of significant algal blooms, although retain phosphorus but to recover and reuse both algal blooms have occurred in sorne enclosed waters, directly as a rich fertiliser or, utilising new extraction e.g. London Docks. Phytoplankton were considered to techniques, retum it as a raw material for detergent and be important in their capacity to convert inorganic other product applications. Clearly this element which material to organic matter, oxygenate water through is not replaceable and essentially rare lends itself photosynthesis and deoxygenate through respiration ideally to the principle of sustainable development. and decomposition. This remarkable recovery has Thus, what is already considered the most effective supported over 115 species of fish and nearly 300 000 builders in detergents would also become the most seasonal water birds. environmentally adaptable. « Phosphate File » 14p. 1997, order direct/y from The challenge now is to ensure that this achievement is SCOPE Newsletter or CEEP, Avenue Van maintained and built upon. As the Thames Estuary Nieuwenhuyse 4. Bte 2-b- 1160 Brussels, Belgium. Environment Management Plan recognises "nowhere in the country are environmental pressures and competing demands for space and resources greater than on Thameside". To achieve "an Estuary which is valued as a place to live, work and relax: an environmental asset and a focus for economie growth" it is vital that resources are managed in a sustainable way. "The Water Quality of the Tidal Thames", Environment Agency Report 1997, ISBN 011 31025 2.

THE PHOSPHATE FILE :AN INFORMATIVE BOOKLET COVERING PHOSPHATE SOURCE, USE AND FATE IN THE ENVIRONMENT

The Centre Européen d'Etudes des Polyphosphates (CEEP), a CEFIC sector group representing the European Phosphate producers, have recently published a 14 page booklet entitled «Phosphate­ File».

Both clear and concise, this booklet was prepared as an informative study of phosphate and the environment. From its geographical extraction sites, its nutritional impact, its uses in agriculture through to an in-depth study of phosphate in the environment, the « Phosphate File » covers ali aspects related to this valuable resource. Moreover with global development, the need for phosphorus is expected to increase in agriculture and industry thereby placing constraints on this valuable finite resource.

7 � � ..

�

The SCOPE Newsletter is produced by the CENTRE EUROPEEN D'ETUDES DES POLYPHOSPHA TES, the phosphate industry's research foundation and a sector group of CEFIC (the European Chemical lndustry Council).

The SCOPE Newsletter seeks to promote a better understanding of the sustainable use of phosphate and the role of phosphate in the environment.

The SCOPE Newsletter is open to input from its readers and we welcome ali comments or information. Contributions from readers are invited on ali subjects conceming phosphates, detergents, sewage treatment and the environment. You are invited to submit scientific papers for resume or full publication, to send comments on the studies mentioned in this Newsletter or other scientific or technical views.

For more information, please contact : Newton Consulting Network- who produce this SCOPE Newsletter- 9, rue Newton, Paris, France, Te133-1-53-57-7698 Fax 33-53-57-7679 e-mail : [email protected]

The SCOPE NEWSLETTER is also available on INTERNET at : http://www.asi.fr/scope

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IN EUROPE

NUMBER TWENTY TWO JULY 1997

in-situ ü.S.A p.l An iron fertiliser experiment was carried out twice, (1993 and 1995), in the eastern Pacifie Ocean to SELECTIVE REMOV AL AND RECOVERY OF observe the effect on phytoplankton abundance. PHOSPHATE USING A NEW .CLASS OF SORBENTS AUSTRALIA p.5 A new class of sorbents - polymerie ligand exchangers (PLE) - have been tested in a ftxed bed column FOOD WEB INTERACTIONS AND allowing the selective removals of phosphate through BIOMANIPULATION ligand type interaction. The sorbent is also amenable to efficient regeneration and phosphate can be The control of phytoplankton biomass in severa! recovered as magnesium ammonium phosphate Australian reservoirs was studied. Food web (struvite), a high value fertiliser. interaction of Australian biota were explored at different levels. In order to manipulate fish 'l'BE NE'l'BERLANDS p.l communities to reduce phytoplankton . biomass a thorough understanding of the process in the plankton­ CALCIUM PHOSPHATE PRECIPITATION IN A associated food web is needed. HXIDIZED BED : A BLACK BOX APPROACH. üNI'l'EDKINGDOM p.6 This paper studies the precipitation features of calcium phosphate in a fluidised bed reactor in a concentration ENVIRONMENTAL FACTORS AND NUTRIENT range between 5 and 10 mg P/1 and establishes the REGULATION IN NATURAL WATERS conditions for optimum phosphate removal efficiency. A method is presented to select process conditions This review seeks to identify the key areas in aquatic where co-precipitation of unwanted phases is avoided. science required for future management of algal problems in freshwaters. üNI'I'EDKINGDOM p.3 SWI'l'ZERLAND p.7 MONITORING OF SOIL DERIVED PHOSPHORUS IN SURFACE RUNOFF SUCCESSFUL WATER PROTECTION MANAGEMENT This paper examines the rates of P transfer from soil to waters from intensively managed grazed grassland by Lake Zurich, Lake Walenstadt and the Zurichobersee surface runoff plus interflow to 30 cm depth, in a make up a connected system of lakes with differing poorly drained soil, in relation to rainfall inputs during population densities, geographical and meteorological 12 months. lt concludes that grasslands are a conditions making them suitable for studying the significant source of diffuse P inputs to surface and effectiveness of water protection measures. esturine waters and may cause eutrophication. PLUS... p.8 'l'HE NE'I'BERLANDS p.4 RECENTL Y PUBLISHED REPORT PHOSPHATE & NITROGEN INFLUENCE FISH "PHOSPHORUS REMOVAL AND RECOVERY STOCKS TECHNOLOGIES"

This report is an inventory of current knowledge, NORDIC ECO-LABELLING SCHEME OPEN FOR carried out at the request of the Duteh Commodity PHOSPHATE BASED DISHWASHING Board for Fish, in response to the debate on the DETERGENTS connection between depleted stocks of flatfish and the considerable reduction in the quantityof phosphate in IAWQ VIDEO ''NATURE'S WAY" coastal waters. BEST MANAGEMENT PRACTICES (BMPs) THE CONTROL OF WATER DIFFUSION PACIF1C OCEAN p.4 NEW WEBSITE FOR ENVIRONMENTAL DRAMATIC CHANGES IN SURFACE WATERS INFORMATION DUE TO IRON ENRICHMENT EXPERIMENT

SCOPE is a non-commercial, non-profit making European association based in Brussels. Ils a1m 1s to provide a platform for objective and scientific informat1on on the effects of phosphate-containing and phosphate·free detergents on the enwonment.

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SCOPE : Scientific Committee on Phosphates in Europe ·Association Sans But Lucratif sise à Bruxelles et soumise à la Loi du 27 juin 1921 Following exhaustion of PLE after phosphate breakthrough more than 90% phosphate was recovered SELECTIVE REMOV AL AND RECOVERY OF in less than 10 bed volumes - both electroselectivity PHOSPHATE USING A NEW CLASS OF reversai at high ionie strength and lower affinity of SORBENTS - 2- H2P04 compared to HP04 provide the reasons for efficient phosphate regeneration. The presence of various competing anions make the selective removal of low concentrations of Phosphate is an anionic ligand and its sorption onto phosphate after secondary treatment particularly DOW 2N-Cu involves electrostatic interaction due to difficult. In this research a new class of sorbents - fixed positive charges in the polymer phase and polymerie ligand exchangers (PLE) - have been accompanying lewis acid-base interaction with tested in a fixed bed column allowing the selective immobilised copper ions. removal of phosphate through ligand type interaction. The sorbent is also amenable to lt bas been demonstrated that a new fixed-bed sorption efficient regeneration and phosphate cao be process is capable not only of removing phosphate recovered as magnesium ammonium phosphate selectively from municipal and industrial wastewater (struvite), a high value slow-release fertiliser. but is also amenable to efficient regeneration leading to phosphate recovery. With the current concem over Phosphorus cao be removed through either chemical nutrient removal from wastewater and water reuse, the precipitation or biological nutrient removal (BNR), process is expected to be an economically viable one and transferred to the sludge phase. in the near future. Water Science Tech. Vol. 33 1996 Department of Civil and Environmental Engineering 4 successive column runs were carried out in the 13E Packer Avenue, Lehigh University, Bethlehem, PA laboratory using treated wastewater from the 18015, US.A. Dongye Zhao and Arup K. Sengupta. Bethlehem Sewage Treatment Plant in Pennsylvania, U.S.A. The objective was to validate: * PLE's high affinity with phosphate compared to CALCIUM PHOSPHATE PRECIPITATION IN A sulphate FLUIDIZED BED : A BLACK BOX APPROACH * extended colurnn runs with complete phosphate removal with synthesised wastewater and secondary Emphasis in recent years bas been focused on effluent improving processes which lead to enhanced * regeneration of the exhausted colurnn for phosphate phosphate recovery - this paper studies the recovery. precipitation features of calcium phosphate in a fluidised bed reactor in a concentration range A specially chelating polymer containing only nitrogen between 5 and 10 mg Pli and establishes the donor atoms (DOW N2) was used as PLE after loading conditions for optimum phosphate removal with copper (11) and 2 other commercially available efficiency. The feasibility of a process based on the resins - IRA-958 (a strong base anion exchanger) and precipitation of magnesium phosphate was shown IRC-718 (a copper loaded chelating exchanger). were for waters with a low calcium content. A method is used for comparison. The resins were conditioned presented to select process conditions where co­ � following the standard procedure of cyclic exhaustion, precipitation of unwanted phases is avoided. and the following chemical analyses were carried out: sulphide, chloride, phosphate, bicarbonate, copper and Currently severa} processes for phosphate removal TOC analyses. based on the precipitation of phosphate salts are used - conventionally a reagent is added to precipitate The breakthrough histories were measured and the phosphorus salt, which becomes incorporated in the influent compositions, pH and operating sludge by-product. hydrodynamic conditions - empty bed contact time (EBCT) and superficial liquid velocity (SLV) were A screening study of a fluidised bed process with high identical for each of the 3 sorbents. The phosphate inlet phosphate concentrations was carried out, by breakthrough for DOW 2N-Cu occurred much later varying conditions such as the inlet concentrations of than for the other sorbents, in spite of high calcium and phosphate and the outlet. Phosphate concentrations of competing bicarbonate, sulphide and removal efficiency, mechanical stability of the chloride. DOW 2N-Cu also offered much higher phosphate grains and the effects of carbon and phosphate uptake capacity than IRA-958. Total anion magnesium ions (which can interfere in the process) exchange capacity was found to be equal to the copper were determined. (Il) loading capacity of DOW 2N, suggesting that fixed copper (11) anions in the polymer provide the The process is based on a precipitation of calcium primary sorption site for anions. phosphate obtained by mixing a phosphate solution with calcium ions and a base. The fluidised bed

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reactors (of 2 different sizes, which did not appear to grasslands are a significant source of diffuse P affect the pro cess) were filled with sand grains and inputs to surface and esturine waters and may then fed continuously with aqueous solutions contribute to eutropbication. containing phosphate ions, calcium ions and a base. Phosphate covered grains were removed from the Seven 1 ha grazed lysimeter plots managed for the past bottom of the bed and replaced regularly with fresh 12 years as intensive grassland at North Wyke, Devon sand grains. At the same time two unwanted processes were monitored. The existing sward is dorninated by occurred leaving small particles ("fmes"): primary Loliurn perenne L and other grass species. The soil is a nucleation in the liquid phase and abrasion of the clayey non-calcareous pelostagnogley of the mineral layer in the bed. The fmes leave the bed with Hallsworth Series. Before analysis water was collected the rernaining phosphate not recovered in the reactor. from each plot lysimeter and channelled through a However aggregation with the fmes and the grains can continuons level recording reservoir and then through contribute to phosphate recovery. The concentrations V-notch weirs. The plots were managed for N studies, of P, Ca, Mg and Na were measured - total carbonate but this involved inputs of triple super phosphate concentration was measured by acid-base filtration, (TSP) fertiliser. An observationallempirical approach fme and grains by X-ray diffraction, the grains were was used, involving both routine and storm also analysed by optical rnicroscopy and scanning monitoring. Modelling the data was difficult as they electron rnicroscopy (SEM). The grains and fmes were skewed by the occurrence of low frequency, high produced appeared to be amorphous calcium intensity events. phosphate (ACP) except for one experiment at the highest P concentration where DCPD ( dicalcium Higher discharge was associated with higher TP phosphate dihydrate ) was formed. concentration although this was not the case for MRP, implying that unreactive P and particulates > 0.45 J.Lm Optimum conversion is the one corresponding to in size play a major role in the export of TP. Thus maximum efficiency - if water does not contain mechanisrns such as hydrolysis and mineralisation of magnesium or carbonate ions the supply of the base organic P and erosion of particulate P may be should promote conversion of 50-60% of the incoming important processes for releasing P from these soils. phosphate: the presence of these ions increased these Patterns of TP concentration and loading and values to 80-95% - most wastewaters are in this latter suspended sediment throughout the period of category. Low conversion values are desirable as they hydrograph were more complex. The delayed peak in imply low base consurnption (an important element TP concentration was associated with the second peak when considering operating costs). The amount of in the suspended sediment , suggesting that sediment base needed to obtain the required conversion can be transfer rather than water movement, as such, was calculated if thecomposition of the water to be treated important. More research is needed to understand the is known. Corresponding outlet pH values were 7.5-9. dynarnics of P runoff, particularly when it is transferred from the soil surface into surface drainage lt was concluded that phosphate removal efficiency in systems. a fluidised bed reactor depends on composition of the water treated : a maximum efficiency of 50% was Release of high concentrations of TP and MRP -1 achieved. This corresponded with a low phosphate (exceeding 1000 !lg 1 ) are thought to relate to input. Wat.Res. Vo/.30, N°7, pp 1677-1685 Laboratory pasture conditions at that time. lt was suggested that 3 for Process Equipment, Delft University of factors were responsible:- 44, 2628 Technology, Leeghwaterstraat CA, Delft, The * short term management history - excreta are a direct Netherlands & !PA P.O.Box 7141, Cidade source of P and have long term effects on the EPC in Universitt:iria, 01064-970, Siio Paulo S.P. Brazil. soils, but the design of the drainage/sampling system M.M.Seckler, O.S.L. Bruinsma & G.M. Van Rosmalen, did not reflect localised nutrient concentration from January 1996. excreta. Introduction of cattle may also have resulted in "poaching" - both dung deposits and poaching were prevalent around drink troughs and gateways in the MONITORING OF SOIL DERIVED plot lysimeters - slurry application and grazing during PHOSPHORUS IN SURFACE RUNOFF periods when the soil was close to saturation lead to much higher !osses of P than during dry periods. The This paper examines the rates of P transfer from release of P may have been exacerbated by the wetting soil to waters from intensively managed grazed and drying cycle. grassland via surface runoff plus intertlow to 30 cm * rainfall intensity - high intensity rainfall may have depth, in a poorly drained soil, in relation to caused erosion of particulate P and contributed to high rainfall inputs during 12 montbs. In order to gain losses of TP compared to MRP. an understanding of the mecbanisms involved total * estimated P loads in grassland soil - a total annual pbosphorus (TP) and molybdate reactive loss of c. 3kg of TP ha - 1 was estimated. pbosphorus (MRP) are considered witb temporal differences in runoff discharge. It concludes tbat

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Association Sans But Lucratif Minimal loss strategies have previously been suggested. If P is added as basic slag rather than TSP a slow release of P would occur when it was ploughed DRAMATIC BIOLOGICAL AND and incorporated into the soil matrix. Direct injection BIOCHEMICAL CHANGES IN SURFACE methods of slurry and sludge additions have been WATERS DUE TO IRON ENRICHMENT suggested to minimise !osses, the use of buffer zones EXPERIMENT has also been discussed. Most loss strategies have focused on arable systems and more research is An in-situ iron fertiliser experiment bas been required to assess the importance of managing carried out twice , in 1993 and 1995, in the eastern grassland. However in sensitive catchments it is Pacifie Ocean in order to observe the effect on advisable to avoid spreading fertiliser and manure at phytoplankton abondance. Despite high times when runoff is likely to occur. Impacts of re­ concentrations of the major nutrients, nitrate and seeding pasture, grazing and pasture differences may phosphate, phytoplankton abondance remains low also be important management considerations in this area. These features characterise the 3 affecting P loss and are important areas for future "high nitrate, low chlorophyll" (HNLC) regions - research. P.M. Haygarth & S.C. Jarvis, ref Wat.Res. including the eastern equatorial Pacifie, the ice-free Vol. 31, W 1 pp 140-148, 1997. Southern Ocean and the Sub Arctic North Pacifie Ocean.

PHOSPHATE AND NITROGEN INFLUENCE Papers report that it is the extraordinarily low FISHSTOCKS availability of iron which limits phytoplankton growth in theseHNCL areas: although iron is almost insoluble This report is an inventory of current knowledge, in sea water, it is an essential trace nutrient required by carried out at the request of the Dutch Commodity phytoplankton for many biochemical processes - e.g .. Board for Fish, in response to the debate on the chlorophyll synthesis and biochemical processes. connection between depleted stocks of flatfish and the considerable reduction in the quantity of Iron Exl, carried out in 1993, reported that a single phosphate in coastal waters. dose of iron raising the dissolved iron concentration to 4nm, over 64km2 resulted in significant increased From 1950-80 amounts of phosphate and nitrogen in phytoplankton abundance and production rate, but had these coastal waters rose considerably, and when limited effect on nitrate concentration or partial levels then fell phosphate suffered a greater decrease pressure of C02. Unfortunately the experiment ended than nitrogen, leading to an excess in nitrogen. abruptly when the fertilised patch sank beneath a layer of less dense water. Although the experiment verified It is probable that plant growth increased with the the iron hypothesis, the issue of whether iron increase in nutrients, leading to a larger number of fertilisation could relieve the HNCL condition was left Seabed organisms ( copepods and decapods) which are unresolved. an important source of nutrition for fish. There appears to be a connection between the increase in nutrients In Iron Exil, carried out in 1995, the same amount of and the survival and increased growth rate of the dissolved iron was added from a ship into the surface �·---­ larvae of plaice and sole - with important positive layer of a square patch of ocean in the eastern consequences for fish catches. equatorial Pacifie, in three sequential infusions over a week, to sustain the increase of dissolved iron in the The decrease in phosphate has lead to disequilibrium 2 over the past 15 years - the nitrogen excess has caused surface layer over 72km . The fertilised patch, tagged an increase in marine phosphorescence, undesirable with a drogued buoy and a biologically inert tracer toxic species of algae (unsuitable for consumption) (SF6), whilst drifting 1500 km. Untreated water and thus negative effects on the food chain; outside the patch served a control.

Restoration of the equilibrium is desirable for both The effect of the fertilisation was immediate and water and fish management, although no decrease in dramatic - phytoplankton photosynthetic capacity nitrogen levels can be expected in the near future and growth rate and abundance increased, whilst nitrate restoration at the current level is undesirable (leading concentration declined by half. As the phytoplankton to an excess of algae). The only remaining option is to bloomed its species composition changed radically - allow the concentration of phosphate to increase. A diatoms became dominant and accounted for most of policy involving a reduction of nitrogen discharges the increased use of nitrate As the bloom developed and an increase in phosphate discharges would thus be the partial pressure of co2 in the middle of the patch the most appropriate and would benefit the fishing decreased rapidly, reducing the ocean-to-atmosphere sector. Marine Biology Research Group, University of C02 flux by 60%. There was also an increase of Groningen, W.J. Wolff, Dr H.J. Nanninga & Dr R. dimethyl sulphide (DMS) in the bloom which may Boddeke 1997. have a role in global warming.

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4 SCIENTIFIC COMMITIEE ON PHOSPHATES SCOPE NEWSLETTER IN EUROPE

However, the stimulated production was short lived - correlation between mean crustacea body length and within a week of the fmal infusion, indicators of the TPB exists, although maximum mean length is much last phytoplankton physiological condition returned to higher (more than 2mm) than elsewhere, suggesting the sarne levels as before, phytoplankton bloom waned that the potential for biomanipulation will be higher. (presumably due to grazing and sinking) - and contrary This larger mean value is due to the presence of the to expectations the was no indication that the iron was zooplankter Daphnia Carinata, a species widespread in retained and efficiently recycled within the biota of the Australia. surface layer. The consequences of larger scale, longer term inputs of iron are uncertain.' The planktivorous fish of Australian reservoirs are relatively small and they may deplete small Iron Exil reinforced the notion that availability of iron zooplankters, resulting in the promotion of this lirnits cell division rates, abundance and production Daphnia. rate in phytoplankton. Although zooplankton increased in abundance and grazing rate, the response was In Lake Dartmouth small flat headed gudgen, insufficient to prevent the diatom bloom. lt also Philypnoden grandiceps, were co-existing with showed that, along with grazing, iron limitation Daphnia Carinata in the pelagie zone, and a positive determines the composition of natural assemblages of correlation between crustacean body length and fish phytoplankton. hon fertilisationdid little to disrupt the acoustic biomass was found. Such interactions suggest natural grazing balance of the small species. The that biomanipulation may involve creating conditions larger-sized phytoplankton are probably under the to protect sorne planktivorous fish. lt was also most stressin HNCLregions, and division rates should suggested that sorne planktivores stirnulate algal be low, although evidence is contradictory. Nature growth by excreting nutrients. Vo/.383 JOOctober 1996 p.475 Bruce W Frost. Final control will depend on which force prevails: zooplankton grazing or nutrient supply from fish and FOOD WEB INTERACTIONSAND other sources. Such complex interactions show the BIOMANIPULATION necessity of analysing a lakes' food web before applying biomanipulation as a management option - The control of phytoplankton biomass in several further development of the food web theory under Australian reservoirs was studied. Food web Australian conditions is needed. CRCFE Murray­ interaction of Australian biota were explored at Darling Research Centre, P.O.Box 921, A/bury 2640, different levels: laboratory trials, in mesocosms, by Australia. Dr V.F. Matveev & L.K. Mateeva 1996. analysing the time series of plankton and fish biomass in reservoirs. In order to manipulate fish communities to reduce phytoplankton biomass a ENVIRONMENTAL FACTORS AND NUTRIENT thorough understanding of the process in the REGULATION IN NATURAL WATERS plankton-associated food web is needed. The aim of biomanipulation is the establishment and This review seeks to identify the key areas in maintenance of a ratio of planktivores/piscivores aquatic science required for future management of sufficient for water quality requirements. algal problems in freshwater. The short ter rn management of problems related to toxic In Lake Hume (surface area 202.5km2, 41m depth) cyanobacterial blooms in the U .K. bas been met by raising the general public's awareness, defining the and Lake Dartmouth (63km2, 170m depth) Daphnia role of public bodies in the matter and introducing biomass accounted for more than 50% of the observed monitoring programmes. variance in total phytoplankton biovolume (TPB) in umm spring/s er '94/95. When zooplankton biomass and Agricultural fertilisers play a major role in nutrients were manipulated in water from the lakes, eutrophication - the change in English lakes in the total chlorophyll-a was significantly affected by 8 1950's was abrupt and coincided with the increased grazers in out of 12 experiments and by added usage of fertilisers for grass production, a population nutrients in 9 out of 12 experiments - the relative increase, an increase in the influx of tourists, the importance of the 2 effects changed seasonally. introduction of piped water, sewerage and secondary Acoustic biomass of pelagie fish (echo integration wastewater treatment - it is impossible to separate above 90dB) also varied seasonally - peaking in these effects. The diffuse and point source of inputs of autumn and having minima in spring. Acoustic fish nutrients from agricultural practices are still ill defined biomass was highest in eutrophie (Queensland) lakes and the effects of nutrient regulation difficult to and lowest in oligotrophic (Snowy Mountains)lakes. predict.

In contrast to other continents, Australian reservoirs The author deduces that if the export of nitrogen and, contain established populations of fish in the pelagie particularly phosphorus is increased there is sorne pro zone. It bas been demonstrated that a strong negative rata increase in the capacity of water to support

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Association Sans But Lucratif primary production. Production is also subject to other protection of drinking water rather than eutrophication constraints, e.g. the availability of light and - methods include crop zonation and reduced fertiliser temperature - different phytoplankton species application. These techniques are developing rapidly differentiated selectively by the interplay of these but their nutrient removal efficiency bas yet to be factors. Although the development of blooms have quantified. Entry of nutrients to lakes can also be been associated with eutrophication and phosphorus reduced using pre-lake techniques, including the concentration, it is not apparent that cyanobacterial installation of treatment plants to remove phosphorus. biomass requires any mass specifie contribution of Most eutrophied lakes have large amounts of phosphorus. phosphorus isolated in their sediments as iron salts or calcite - this is a particularly effective solution in It is imperative to understand that it is a question of smaller, shallower lakes. dynamics - bloom forming cyanobacteria are one of * Physical controls - these are really only applicable in the slowest and most light sensitive phytoplankton lakes, since the effects of river morphology on species. This is the main link between cyanobacterial eutrophication is not well enough understood - the blooms and eutrophication: the avoidance of most commonly used method for long term cyanobacterial production is not a question of eutrophication control is artificial destratification, eliminating all phosphorus inputs, but ensuring which aims at breaking down lake stratification in __ optimal physical and chemical conditions. summer months. W ork in the Lund Tubes in Blelham Tarn suggests that intermittent destratification There is a wide range of different forms of phosphorus enhances this method by creating instability in the which differ in their availability for uptake by algae. algo-community resulting in no dominant species. the main agricultural export is in particulate form - Although this clay, fme sand and detritus. Its role in eutrophication is method is attractive in cost terms there is controversy considered to be subordinate to secondary sewage over its efficacy and few lakes in the U .K. are deep treatment - demonstrated by the rapid improvement in enough for it to be used. the condition of lakes benefiting from tertiary * Bioremediation - recently much work on the wastewater treatment. understanding of biological process in lakes has been done, leading to the development of "ecotechnical As most biological material produced is destined for methods", manipulating the trophic status; the permanent sediment, it must be considered how Biomanipulation is essential in the restoration of often components can be reused in biomass shallow lakes with high rates of phosphorus sediment formulation before being buried. Much of the flux of recycling. phosphorus is held in iron (III) hydroxide and reuse depends on reduction of the metal to the iron (II) form. However, since concentrations of available phosphorus required to control primary production are very low 1 The released phosphorus is biologically available to (5-10 J.lg 1- total dissolved phosphorus) the reduction the organisms in contact with it, thus the significance of nutrients from any one source will be ineffective. -� given to solution events is understandable. However, it The National Rivers Authority bas developed a is unclear how well this phosphorus is used, as it framework for gathering and presenting scientific generally remains isolated from production sites in evidence including the publication of "Action Plans"--� surface waters. Deep lakes do not tend to recycle on a case by case basis. This should then be subjected phosphorus, whilst shallow lakes do so almost to a cost-benefit analysis to achieve agreement of all continuously - in shallow lakes containing those involved before the plan is implemented. Excerpt macrophytes, the macrophytes take up and accumulate from the RC Publication "Agricultural Chemicals and nutrients from the water and sediment. the Environment" 1996 ISBN 0-85404-220-2 pp27- 4J.A.J.D. Ferguson, M.J Pearson & C.S. Reynolds. A combination of various factors acting serially drives the seasonal changes in mass and species composition in the planktonic community, offering a choice of SUCCESSFUL WATER PROTECTION solutions to combat eutrophication. The extent of the MANAGEMENT influence of any one mechanism must be considered when selecting a control method. Techniques may be Lake Zurich, Lake Walenstadt and the categorised accordingly: Zurichobersee constitute a connected system of * Nutrient removal - the most important point sources lakes with differing population densities, of phosphorus are those from wastewater treatment geographical and meteorological conditions thereby plants, thus control of phosphorus loading is achieved making them suitable for studying the effectiveness by precipitation of phosphorus with iron salts or by of water protection measures. biological removal. * Catchment management - This is a longer term Although there is little research on the lakes before approach although methods to reduce diffuse sources 1950, it is known that the eutrophication of Lake -­ of nitrogen have already been adapted for the Zurich began around 1890. Stepwise wastewate1

6 SCIENT! FIC COMMITIEE ON PHOSPHATES SCOPE NEWSLETTER

IN EUROPE

treatment, with both mechanical and biological stages, Zurich pay 3.06 SFr/m3 for bath drinking water and was introduced in the 1950's and 1960's, which greatly wastewater treatment. reduced amounts of DOC, TOC and BOD. In the 1970's phosphate precipitation by chemical means was Overall water protection measures in the area are introduced, leading to a lower phosphorus input, effective, leading to better quality lake water, which in reflecting a decrease in phosphorus concentration. tum is processing to excellent drinking water.l996 However a significant reduction in algal biomass is Water Supply, Vo/.14, N°s 314, 415-437. Zurich Water only observed when phosphorus concentration sinks Supply Authority, Quality Control, Hardhof 9 below 5 Jlg 1-l, and even then a delayed reaction of the P. O. Box, CH Zurich, Switzer/and. H.P. Klein & U. phytoplankton biomass over severa! years must be Zimmermann. expected (as in the case of Lake Walenstadt). Between 5 - 60 Jlg I-1 no sporadic mass development occurs, but neither is there any marked reduction of the RECENTLY PUBLISHED REPORT­ average algal biomass of 1 to 2 mg/1. When "PHOSPHORUS REMOVAL AND RECOVERY TECHNOLOGIES" phosphorus concentration is above 60 Jlg I-1 short periods of moderate mass development can occur , The Imperial College of Science and Medicine bas although they have little negative effect on the lake (as carried out a world-wide review of the scientific and in the case of Lake Zurich). Currently there is no technical possibilities for the recovery and recycling of information on the biomass development at higher phosphorus in sewage. The report was sponsored by phosphorus concentrations, since the influx of the phosphate industry's research foundation, with the phosphorus into the lake is limited by protection aim of stimulating discussion and subsequent research­ measures resulting in a maximum concentration of 130 development into the recovery of this essential 1. Jlg 1- resource. SCOPE subscribees will be receiving a copy of this report. If you wish to obtain a five page Between 5-60 J.Lg 1-1 phosphorus, changes in synopsis please contact E.C.U who publish this phytoplankton composition are observed e.g. as newsletter for SCOPE (see back caver for details). S. phosphate levels feil blue-green algae, particular1y the Brett, G.K. Morse & J.N. Lester. Environmental and genus Oscillatoria, reappeared in Lake Zurich. The Water Resource Engineering Section, Imperial Co/lege biomass of zooplankton is dependent on the supply of of Science, Technology and Medicine, 1997. ISBN 0 phytoplankton, as a consequence the decrease of 9484ll JO 0 certain algal groups of phytoplankton was followed by a decrease in zooplankton. THE NORDIC ECOLABELLING SCHEME The ban on phosphates in detergents (198 6) has had no OPEN FOR PHOSPHATE BASED additional effect on the phosphate content of the lakes DISHWASHING DETERGENTS investigated. The residual concentration of phosphate in the outflow from wastewater treatment plants is Since 1989 a voluntary, positive ecolabelling scheme largely independent of phosphate concentration in bas been operating in Finland, Norway, Sweden and untreated wastewater. Iceland with the aim of informing consumers in the selection of products which are !east harmful to the As far as drinking water processing from lake water is environment. The criteria for the ecolabel, the Swan, concemed further reduction of phosphate is are based on a product's environmental impact unnecessary. The effect of phosphate fluctuations throughout its lifecycle. A recent criteria document between 5-60 Jlg 1-1 on biomass is srnall, thus covering dishwasher detergents has been published by replacing phosphate in detergents with other chemicals the Nordic Ecolabelling board. The document states is questionable, particularly as their effects and that "phosphate and other phosphorus compounds may degradation in lakes and drinking water are not yet be included ". - and the Swedish lnstitute of Standards known. The flocculation filtration stage now in place (SIS) has decided that products containing up to 53% in the waste-water treatment process has been found to STPP are eligible for the Swan label. This decision of be effective in removing bath phosphate and organic theNordic Ecolabelling Board recognises STTP as an substances from wastewater. environmentally acceptable builder for detergents.

The costs relative to waste-water pollution and eutrophication problems are enormous and include waste-water treatment, lake water protection and continuing drinking water processing. Capital costs are a continuing burden to water supply authorities - the depreciation period for the plants is 40 years. Users in

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Association Sans But Lucratif . ; .. 1bis 26 min. video is available for a processing IAWQVIDEO "NATURE'S WAY" charge of f9.50 from: BEST MANAGEMENT PRACTICES (BMPs) International Association of Water Quality (lAWQ) THE CONTROL OF WATER DIFFUSION Duchess House, 20 Mason's Yard This new video has been produced to introduce a Duke Street St James's range of Best Management Practices (BMPs) and London, SWlY 6BU sti.mulate interest in these control approaches to ENGLAND diffuse pollution. The video illustrates the principles developed from research, working into practice and NEW WEBSITE FOR ENVIRONl\tiENTAL seeks to encourage techniques of source control and INFORL'\1ATION treatment train approaches. The video is designed for Drs. G. Fred Lee and Anne Jones Lee who have been a wide audience including water agencies, land users, active for many years in the field of eutrophication­ developers, urban/agricultural engineers, regulators ... related water quality have now begun to publish their Particular attention is given to : papers and reports on their web site - grass swales and buffer zones/strips http://members.aol.cpomlgfredlee/gfl.htm. Further - infiltration systems information on the site and the publications can be - wet ponds obtained from Dr. G. Fred Lee at [email protected]. - stormwater wetlands

The SCOPE Newsletter is produced by the SCIENTIFIC COMMITTEE ON PHOSPHATES IN EUROPE, a non commercial, non profit-makin association (Association Sans But Lucratif) based in Brussels. The association includes international groups headquartered in Belgium, France, Spain, Sweden and the UK, producers of a wide variety o detergent ingredients including phosphates. Its aim is to provide a platform for objective and scientific information on the effects of phosphate containing and phosphate-free detergents on the environment. The SCOPE Newsletter is open to input from its readers across Europe and we welcorne ail comments or information. Contributions from reader are irivited on ail subjects concerning phosphates, detergents, sewage treatment and the environrnent. You are invited to submit scientific pape for summary to send comments on the studies mentioned in this Newsletter or other scientific or technical news.

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E.C.U. (European Communications Unit) • who produce this Newsletter for SC OPE 20, rue de l'Arcade, 75008 Paris, France, Tel.+ 33 1 44 94 80 70 Fax +33 1 44 94 81 01 E-mail [email protected]

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NUMBER TWENTY FEBRUARY 1997

UNITED KINGDOM p.2 EUROPE p.4

PHOSPHORUS LEACHING INVESTIGATED IN LAKE RESTORATION GUIDE LAUNCH THE BROADBALK EXPERIMENT A Guide to the Restoration of Nutrient Enriched Movement of P vertically through and out of soil Shallow Lakes, jointly produced by the Broads is generally considered to be of little importance, Authority and the Environment Agency, is unless soils become P saturated (following heavy supported by the European Commission through manure applications), due to high P fixation its LIFE programme. capacity of soils. Factors controlling these losses are generally considered to be related to soil type, SWEDEN p.4 pH and weather rather than fertiliser use. These findings have been questioned by data from the BUILDERS IN DETERGENTS : Broadbalk Continuous Wheat Experiment at CITRATES, PHOSPHATES AND ZEOLITES Rothampsted. Over the last few years the laundry detergent UNITED KINGDOM p.3 market has seen the development of alternative builder systems, moving away from conventional ACID LAKES TREATED WITH PHOSPHATE laundry detergents. Numerous studies have SOLUTION shown that the impact on the natural environment of these substitutes is insignificant Lakes acidified by airborne pollutants typically as a result of this substitution. have low biological productivity and support an impoverished flora and fauna. Although they can AUSTRALIA p.5 be neutralised by adding base (lime), the resulting calcium rich water supports animal and THE FILTER TECHNIQUE FOR SEWAGE plant communities unlike those in natural EFFLUENT TREATMENT softwater lakes. This paper examines the results of a 3 year experiment, a pretreatment year, A filter technique for sewage effluent treatment followed by 2 years of fertilisation, in the Lake has been developed in the Murray River Basin in District. Australia, as a cheaper and more sustainable alternative to existing land treatment systems. lt UNITED KINGDOM p.3 aims to provide a sustainable and economically viable land treatment system. Nutrient rich ". A TOOL FOR RESTORATION : effluent for intensive cropping was used, with

BIO-MANIPULATION IN SHALLOW LAKES • filtration through the soil to a subsurface ZOOPLANKTON AND MACROPHYTE drainage system. INTERACTION UNITED KINGDOM p.6 This paper questions the traditional 'bottom -up approach' and thus traditional restoration PUBLIC PERCEPTION AND WATER QUALITY methods focused on reducing nutrient levels, MANAGEMENT most particularly phosphate levels. The lake restoration programme in the Norfolk Broads This paper examines the factors which have the began in 1980, with the removal of phosphorus 90% greatest impact upon the general public's from sewage effluents. Despite a reduction assessment of environmental quality, and most in phosphorous to Barton Broad, the lake particularly their perception of water quality. lt remained dominated by phytoplankton. ln shows that those responsible for the contrast, this research focuses on top-down management of surface water quality must processes such as fish- zooplankton recognise the need to apply a range of phytoplankton interactions and their importance management strategies including a consideration in the restoration of eutrophie lakes. of the public's perception of water quality and the impact of this upon their use of rivers and beaches for recreation and amenity.

SCOPE is a non-commercial, non-profit making European association based in Brussels.

� lts aim is to provide a plattorm for objective and scientific information on the effects of phosphate·containing and phosphate-free detergents on the environment.

SCOPE NEWSLETTER 1 produced by European Communications Unit - 20, rue de l'Arcade - 75008 PARIS - FRANCE -Tel. + 33 1 44 94 80 70

SCOPE : Scientific Committee on Phosphates in Europe - Assoctatton Sans But Lucrattf stse à Bruxelles et soumtse à la Lot du 27 JUin 1921 """

--,

crop P offtakes were generally greater at the higher PHOSPHORUS rates of applied N. LEACHING INVESTIGATED IN THE BROADBALK EXPERIMENT There was a large variation in both total P concentration and the relative contribution of the P­ fractions between the 5 events and the 5 plots. Soils Movement of P vertically through and out of soil with similar Olsen-P concentrations had comparable is generally considered to be of little importance, P concentrations in the drainage water. DRP was the unless soils become P saturated (following heavy largest fraction in the drainage water and remained manure applications), due to high P fixation low (<0.15mg L"1) from plots below 60mg Olsen-P capacity of soils. Factors controlling these tosses kg·1, when there was then a rapid increase in DRP up are generally considered to be related to soil type, to the maximum Olsen-P concentration pH and weather rather than fertiliser use. These findings have been questioned by data from the These findings, shawn on a simple Split Une mode!, Broadbalk Continuous Wheat Experiment at imply that below the change point the small lasses Rothampsted. were not related to Olsen-P concentrations. Beyond this point P lasses in drainage water were more ·" For more than 1 00 years plots in the experiment have closely related to Olsen-P concentrations. annually received, either no P, P in farmyard manure (FYM) or in inorganic fertiliser (superphosphate), and The P leaving the plow layer could have passed to now contain a wide range of sodium bicarbonate­ the drains by preferential flow in large cracks through extractable P (Oisen-P) concentrations in the plow the subsoil or, less likely, rapid transport of Pin forms layer (0 to 23cm). This is, in part, due to differences less susceptible to sorption but finally measured as in P offtakes by wheat given different rates of N DRP. These processes will be investigated further. fertilisers and grown on soils given the standard rate of fertilisers. The aim of the measurement was to see If soil P concentrations continue to increase in the if significant quantities of P were lost through future there could be an enhanced risk of P leaching. drainage and the relationship to P concentrations in This may happen particularly in areas of high the plow layer. livestock density. Further research is necessary in arder to better predict P dynamics, with regard to bath lt has previously been demonstrated that about 35% fertiliser efficiency and better environmental of P inputs to natural waters now come from protection. agriculture in the U.K., 70% in Denmark and 38% in Germany: these percentages but not necessarily the This research has been sited in the ENDS report 263 amounts could rise with the increasing control of December 1996, page 10. industrial and municipal discharge. Quote «ln a study sponsored by the Ministry of Agriculture and the European Commission, Dr Philip Drainage water analyses were made on 20 plots on Brookes and colleagues have found that excessively each of five occasions between October 1992 and in fertilised cultivated soils can also leach soluble ----. February 1994, before and after the installation of a phosphate. The result was surprising ' Leading new drainage system (September 1993). Drainage experts in the world said it couldn't happen ' Dr water samples were collected from 20 different plots Brookes told ENDS. »G.Heckrath, P.C. Brookes, P.R. Pou/ton, and K. W T. Goulding. The Journal of on 5 occasions, after the drains (at 65cm depth) had 24, 5, 1995 been running freely, each time. The drainage water Environmental Quality. Vol no Sept/Oct was then filtered. Total particulate P (TPP) was calculated from the difference between TP (total P) and TDP (Total dissolved P). Dissolved organic P ACID LAKES TREATED WITH PHOSPHATE (DOP) was calculated from the difference between SOLUTION TOP and DPR. Average Olsen P concentrations in soil were also obtained. Lakes acidified by airborne pollutants typically The lowest Olsen-P concentration occurred in the have low biological productivity and support an plot which had never received any form of phosphate impoverished flora and fauna. Although they can fertiliser (the nil plot). The next lowest concentrations be neutralised by adding base {lime), the were found in the plots receiving half the annual resulting calcium rich water supports animal and standard rate of superphosphate. Plots treated with plant communities unlike those in natural FYM and the standard rate of superphospahte had softwater lakes. This paper examines the results more Olsen P ranging from 72mg P kg·1 to 90m Pkg·1• of a 3 year experiment, a pretreatment year, A general trend for plots with higher N rates to have followed by 2 years of fertilisation, in the Lake lower Olsen-P concentrations was noted, since the District.

2 SCIENTIFIC COMMITIEE ON PHOSPHATES SCOPE NEWSLETTER

IN EUROPE

lt demonstrates that the modest addition of phosphate to stimulate primary production allows the A TOOL FOR RESTORATION : highly efficient generation of a sufficient ba�e , by BIO-MANIPULATION IN SHALLOW LAKES -THE nitrogen assimilation to raise the pH of ac1d lake FISH-ZOOPLANKTON INTERACTION waters. The phytoplankton growth required to bring about this change was modest and did not cause any unacceptable changes in the qualitative composition This paper questions the traditional 'bottom -up of the lake's community. approach' and thus traditional restoration methods focused on reducing nutrient levels, The quantity of base generated depends on many . most particularly phosphate levels. The lake factors , including the flushing rate of the bas1n, the restoration programme in the Norfolk Broads rate of incorporation into the sediment and gaseous began in 1980, with the removal of phosphorus transfers to the atmosphere. Seathwaite Tarn, an from sewage effluents. Despite a 90% reduction upland reservoir, was chosen due to its moderate in phosphorous to Sarton Broad, the lake acidity (pH 5) one main inflow and a gauged outflow. remained dominated by phytoplankton. ln contrast, this research focuses on top-down Most of the phosphorus added was rapidly processes such as fish- zooplankton - _ assimulated by growing phytoplankton, p�rticularly phytoplankton interactions and their importance 'nanoplankton', which were consumed 1n large in the restoration of eutrophie lakes. numbers by filter feeding crustacea, accelerating the rate at which the fixed carbon is deposited in the Grazing by zooplankton can r�duce chlorophyll a deep sediment. concentrations. However predat1on by planktlvo�ous fish during the summer prevents such populations The treatment will work best for lakes with a from developing in most of the lakes studied (in the A residence time in excess of a year. modest initial Norfolk Broads). acidity and a sustained loading of nitrogen from the atmosphere or catchment is also desirable. lnducing lt has been shown by artificially reducing these �sh small increases pH (0.5 in this case) is worthwhile, populations from sorne of the�e lakes, the result�ng since it may markedly reduce the metal content of increase in zooplankton grazmg has reduced the polluted waters. Poor productivity in acid waters is chlorophyll a concentration creating �lear wate:r a�d usually associated with poor supplies of phosphorus. allowing the establishment of aquat1c vegetat1on 1n ln addition to the increase in zooplankton in the lakes. Seathwaite tarn there have already been signs of an improved growth rate of the seant brown-trout This biomanipulation provides a good tool which population. could be used by lake managers (see a_Jso t�e following article on best ma!lagement pract1�es) 1n ln practical terms it is difficult to dissolve. calc!um the planning of the restorat1on of lakes wh1ch a�e carbonate, whilst phosphate can be eas1ly added 1n a plankton dominated instead of nutrient removal. Th1s concentrated form. ln this experiment 5.9m3 of method is more effective in shallow lakes as the phosphate solution was added, whereas it would zooplankton may be able to switch to sediments as �- 34 have taken tonnes of calcium to obtain similar an alternative food source wh en the phytoplan kton results. Moreover the phosphorus solution does not population is reduced . result in an unnatural chemistry and the pH is restored to pre-acidification levels rather than to lt has also been demonstrated that in unmanipulated unnaturally high levels. The addition of phosphate broads there is a significant positive correlation can clearly be cost effective, particularly if there is between large grazing zooplankton and macrophyte ultimately considerable recycling of phosphorus. biomass. ln addition the least number of fish were found associated with dense macrophytes, This study shows that it is possible for phosphate to corresponding with extremely low predation pressure. have beneficiai environmental effects and that lt is clear that macrophytes provide a refuge for eliminating phosphate may increase problems of low grazing zooplankton . and thus a _long term productivity and acidity. accumulation of nutnents may ass1st 1n_ the lnstitute of Environmental and Biological Sciences, maintenance of low algal standing crops. These Lancaster University. lnstitute of Freshwater Eco/ogy, & macrophyte dominated lakes have a greater Ambleside. W.Davidson, D.G.George proportion of pike to prey species than plankton N.J.A.Edwards. Nature vo/37712 Oct 1995 dominated lakes.

Water for chemical analysis and zooplankton samples from 3 lakes (Upton Broad, Hoverton Litte Broad and a fish enclosure in a nearby isolated bay) were collected regularly during 1992/3. Fish removals

3

Association Sans But Lucratif were carried out using non destructive techniques, way to assist in this process, and it may be an mainly electrofishing. Fish removal was thought to essential step in the restoration of shallow lake have reduced the fish population by at least 90%. G.L.Phillips, M.R.Perrow & J.Stansfield. Aquatic Hoveton Little and Upton Broads provide good predators and their Prey Chapter 22 - 1996. examples of the contrasts seen in the plankton of the Broads. ln Hoveton Little Broad D.hyalina only occurs for a short period associated with a spring clear water BEST MANAGEMENT PRACTICES phase. Clearly planktivorous fish in this kind of LAKE RESTORATION GUIDE LAUNCH environment rapidly reduce the populations of these larger cladocerans, leaving the zooplankton dominated by smaller species such as B.longirostris A Guide to the Restoration of Nutrient Enriched in the summer. Shallow Lakes, jointly produced by the Broads Authority and the Environment Agency, is ln Upton Broad moderate populations of D.hyalina supported by the European Commission through occur Jan - July, when macrophytes become weil its LIFE programme. _, established in the lake, and weed associated cladoceran species are found. ln the absence of The first comprehensive handbook linking up-to-date planktivorous fish in this lake and in the fish science with practical techniques to solve one of the enclosure, large cladoceran species are predominant environment's most pressing problems has been throughout the year. launched.

When planktivorous fish were removed from these The guide outlines how to deal with eutrophication. lt lakes, such as in the fish enclosure, it is clear that is aimed at lake managers across Europe, and despite zooplankton population cycles low chlorophyll includes a step-by-step strategy for restoration based concentrations could be maintained. This form of on a sound ecological approach. The Environment biomanipulation seems to be a practical way of Agency is developing a strategy for handling creating clear water conditions provided the control of eutrophication and will be consulting organisations the fish population continued. with a particular interest. A Guide to the Restoration of Nutrient Enriched Shallow Lakes. Brian Moss, ln many other European lakes biomanipulation University of Liverpool, Jane Madgwick, the Broads carried out on only once or twice has led to a shift in Authority, Geoffrey Philips, the Environment Agency. community structure of the lake, maintained over Jan 1997. ISBN 0-948119-29-2 many years. This was almost always in association with the rapid development of aquatic vegetation. The mechanism is still unclear although vegetation uptake BUILDERS IN DETERGENTS : and the physical nature of the plants are thought to CITRATES, PHOSPHATES AND ZEOLITES play a major role. The role of piscivorous fish in determining lake structure is also unclear. Initial observations support the view that high pike biomass in relation to planktivorous fish is linked to Over the last few years the laundry detergent macrophyte dominated lakes and restructuring of the market has seen the development of alternative builder systems, moving away from conventional fish community is likely to be an essential final step in the permanent restoration of these lakes. laundry detergents. Numerous studies have shown that the impact on the natural lt has been shawn in published relationships that as environment of builders is insignificant. far as biomass and nutrient supply are concerned ali Citrates, phosphates and zeolites were studied : lakes tend to follow the same general curve. none were found to have taxie effects, and no Concerning summer chlorophyll a and total negative effects on the environment were fou nd. lt is phosphorous the data can be divided into two tobe noted that phosphate free detergents contain categories : those lakes dominated by phytoplankton, many more surfactants which may have a higher rate and those by macrophyte. Biomanipulated lakes fall of toxicity. between these two groups, and suggest that within a range of phosphorous concentrations either plankton Phosphates are most efficiently removed during or macrophyte states can form stable communities advanced waste water treatment, thus allowing more scope for recycling. Citrates decay biologically in the without any further artificial intervention. waste water treatment implying no burden to the A simple nutrient supply reduction to a lake will not recipient. necessarily result in the desired reduction in algal 52:197-203. growth, except if the food webs are able to VATTEN Lund Andreas Bjorklund, restructure. Biomanipulation can be considered as a Stefan Mattsson and Gunnar Karlsson.

4 phase were comparable to those obtained overseas THE FIL TER TECHNIQUE FOR SEWAGE in weil managed land treatment systems. EFFLUENT TREATMENT Another potential use for the system has been identified in a separate trial involving spiking the A filter technique for sewage effluent treatment effluent with the full range of pesticides used in agricultural enterprises in the area. Pesticide loads has been developed in the Murray River Basin in 98%. Australia, as a cheaper and more sustainable were reduced by more than Modified FILTER alternative to existing land treatment systems. lt systems may be used to treat commercial and aims to provide a sustainable and economically industrial effluents containing heavy metals and viable land treatment system. Nutrient rich chemicals, feedlots, piggeries and dairies. effluent for intensive cropping was used, with Water November!December 1996 pp18-21. filtration through the soil to a subsurface & drainage system. N.S.Jayawardane J.B/ackwe/1

The Environment Protection Agency (EPA) promotes sewage effluent treatment by land application to reduce nutrient and other pollution of water bodies PUBLIC PERCEPTION AND WATER QUALITY and to minimise waste generation. However in certain MANAGEMENT areas of Australia land treatment effluent is often less economical than other treatment techniques due to the cost of winter and wet weather effluent storage on This paper examines the factors which have the high value urban lands. The low permeable clay soils greatest impact upon the general public's dominating the urban areas of eastern Australia are assessment of environmental quality, and most also prone to waterlogging and salinisation which particularly their perception of water quality. lt may reduce the long term sustainability and shows that those responsible for the economie viability of the effluent application sites. A management of surface water quality must need was identified to develop a technique adapted recognise the need to apply a range of to overcome these problems. management strategies including a consideration of the public's perception of water quality and the FILTER (Filtration and lrrigated cropping for Land impact of this upon their use of rivers and Treatment and Effluent Reuse) combines the usage beaches for recreation and amenity. of nutrient-rich effluent for intensive cropping with filtration through the soil to a sub-surface drainage The general public's initial perception of river and system. This is carried out during periods of low coastal environmental quality is often based solely growth activity and high rainfall, thus eliminating the upon visual and odorous characteristics. These need for effluent storage. factors bear very little relation to actual physico­ chemical or biological water quality. The system is regulated to ensure adequate nutrient

,_ · removal and so produces low-nutrient drainage ln recognition of the importance of these factors to waters. This filtration phase could be followed by a the general public the National Rivers Authority cropping phase to remove any nutrients stored in the (NRA), the principal regulator of water quality in soil, if necessary, thereby ensuring a sustainable England and Wales, has developed a new General system. Specifie combinations of filtration and Quality Assessment (GQA) scheme, which includes cropping phases used depend on site conditions. consideration of the aesthetic impact of pollution parameters for the first time. Total phosphorus and total nitrogen concentrations in the drainage waters were reduced weil below EPA Research was carried out 1992-1994 to evaluate the target limits of 1.0mgL·1 and 15mgL·1 respectively. importance of individual water quality impairment Total phosphorus and total nitrogen loads were parameters ; foaming, litter, coloured effluents, and reduced by 96% and 85% respectively. sewage derived waste products to perceived water quality and the use of rivers and beaches for The effluent showed presence of blue-green algae recreation and amenity. whilst the drainage water did not, thanks to the increase in the N :P ratio (from 3 to 23), coherent with ln theory the presence of sewage derived previous research which has showed the threshold to contaminants should have the greatest negative be approx. 12. impact on the enjoyment of a visit to a river or beach. However people failed to recognise sewage derived The crops selected for the plots were relatively products, either because they are not familiar with waterlogging and moderately salinity tolerant, so crop them or because of an unwillingness to mention yields and nutrient removal rates during the filtration specifie products. Solid waste contaminants were

5 more disturbing in the water than on the beach or the water quality. This highlights the importance of a weil banks of a river. Single items of derived sewage thought out strategy in any public discussion of waste seemed to have a greater impact than a factors such as phosphate in the environment. conglomeration of items. A large proportion of the public did not identify these products as coming from Public Perception and Water Qua/ity Management. the water. MargaretA. House : Middlesex University, Queensway, Enfield, U.K. ln conclusion it can be seen that there is a gap between the « real » versus « apparent » effect in

The SCOPE Newsletter is produced by the SCIENTIFIC COMMITIEE ON PHOSPHATES IN EUROPE, a non commercial, no profit-making association (Association Sans But Lucratif) based in Brussels. The association includes international groups headquartered in Belgium, France, Spain, Sweden and the UK, producers of a wide variety of detergent ingredients including phosphates. lts aim is to provide a platform for objective and scientific information on the effects of phosphate-containing and phosphate-free detergents on the environment. The SCOPE Newsletter is open to input from its readers across Europe and we welcome ali comments or information., Contributions from readers are invited on ali subjects conceming phosphates, detergents, sewage treatment and the environment.i You are invited to submit scientific papers for· summary to send comments on the studies mentioned in this Newsletter or othe scientific or technical news.

For more information, please contact : E.C.U. (European Communications Unit) - who produce this Newsletter for SCOPE 20, rue de l'Arcade, 75008 Paris, France, Tel. + 33 1 44 94 80 70 Fax +33 1 44 94 81 01 E-mail [email protected]

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N°4 N·s N"12 N"16 SCIENTIFIC ------��-�-�� COMMITIEE ---�---��-�' ---· .. ON PHOSPHATES SCOPE NEWSLETTER ---- � IN EUROPE

NUMBER NINETEEN DECEI\1BER 1996

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AUSTRALIA p.3 NORWAY p.2 ANALYSIS ON THE TOXICITY OF COMMERCIAL NORWEGIAN RESEARCH PROGRAMME BASED AVAILABLE LAUNDRY DETERGENTS ON ON NUTRIENT INPUT INTOTHE SEA NATIVE FRESHWATER CERIODAPHNIA DUBIA RICHARD The state owned conglomerate Norsk Hydro bas launched a five year research programme called Tests were carried out on 20 Australian, and 4 British Maricult (funded in part by the European Commission) laundry detergents, purchased in Sydney during June designed to consider the cultivation of marine 1994, to determine the relative impact of phosphate ecosytems. It will study the opportunities and containing and phosphate free formulations in view of constraints for a more comprehensive use of the oceans the lack of knowledge on their toxilogical effects on the in order to improve our prospects for a larger, yet Australian environment sustainable harvest of marine resources in the future in an environmentally acceptable way involving the NORWAY p.3 addition of nutrients.

INPUTS TO THE OCEAN AND RESULTING SPAIN p.2 POLITICAL DEMAND FROM THE SCIENTIFIC COMMUNITY LEADS TO DESIGN OF A 3D MO DEL A REAL LIFE STUDY ON THE CONSUMER'S This paper describes a model to calculate mass and SHOPPING BASKET volume transport and primary production throughout An interesting study was carried out on nine different the North Sea. This was the first time su ch a 3D conventional and compact detergents, bought in a baraclinic hydroclynamical model bad been coupled to supermarket in Spain, containing STPP or other a chemical biological model in order to better builders, used for washing textiles. 5 were conventional, understand these parameters. In response to political of which 3 contained STPP ; and 4 were compact, of pressure to understand the impact of a 50% reduction which 2 contained STPP. of nutrient input, Morten D. Skogen et Al. ran the model for the year 1985 with specified time series of riverine and atmospheric inputs and they reran it with a 40% reduction. The authors conclude it would be a GERMANY p.3 useful tool for political and environmental planning.

BIOREMEDIA TION OF AN OLD FUEL OIL­ p.4 CONTAMINATED SITE USING U.K. HEXAMETAPHOSPHATE

Groundwater is often found to be contaminated with CLASSIFICATION AND ASSESSE MENT OF various organic chemicals whereby heterotrophic WATER QUALITY IN LAKES bacteria dominate. Phosphate is a required electron acceptor, an essential nutrient, and an important This paper studies the way water quality can be limiting factor of hydrocarbon degradation in assessed in standing waters ; a subject which bas, until bioremediation. recently, with the introduction of European legal requirements, attracted very little attention. A scheme This case concerns contamination, 40-50 years ago, by is described to assess, classify and monitor water and a leaking pipeline, of 15 000-17 000 L. Most of the oil ecological quality in standing waters greater than 1ha tloating on the groundwater was removed in the 70's ; in area in England and Wales, though is normally the pollution now lies 4-9m below ground level. applicable to North West Europe.

SCOPE is a non-commercial, non-profit making European association based in Brussels. Ils a1m is to provide a platform for objective and scientific information on the effects of phosphate-containing and phosphate·free detergents on the environ ment

SCOPE NEWSLmER produced by European Communications Unit- 20, rue de l'Arcade- 75008 PARIS- FRANCE- Tel.+ 33 1 44 94 80 70

SCOPE : Scient1f1c Corr�m�ttee on Phosphates in Europe· Association Sans But Lucratif sise à Bruxelles et soum1se à la Lo1 du 27 Juin 1921 A large nutrient supply may increase both fish production and sediment rate, leading to an advanced an accelerated NORWAY carbon accumulation rate on the seabed. Even if at present it is difficult to imagine artificial fertilisation of the sea as NORWEGIAN RESEARCH PROGRAMME BASED a viable prospect for removing C02 from the atrnosphere, ON NUTRIENT INPUT INTO THE SEA it may weil become a future option.

The results of this project will contribute significantly to highlight and clarify important aspects of the The state owned conglomerate Norsk Hydro bas environmental impact of nutrient discharge into marine launched a five year research programme called systems and thus increase our knowledge on the effects of Maricult (funded in part by the European Commission) nutrient dosage and biological indicators of eutrophication. designed to consider the cultivation of marine ecosytems. It will study the opportunities and The Maricult Research Programme. Hydra Porsgrunn constraints for a more comprehensive use of the oceans Industria/ Park P.O. Box 1 JO, 3901 PORSGRUNN. in order to improve our prospects for a larger, yet sustainable harvest of marine resources in the future in an environmentally acceptable way involving the addition of nutrients.

SPAIN Overfishing bas resulted in reduced global harvests of major fish stocks in the recent past . The problems associated with managing these stocks bas been put on the A REAL LIFE STUDY ON THE CONSUMER'S national agenda. SHOPPING BASKET

The richest fishing grounds are found where there is a continuous flow of nutrient rich deep water to the surface An interesting study was carried out on nine different resulting in short, efficient food webs. Typical areas cao conventional and compact detergents, bought in a be found off the coast of Chile and Namibia. These supermarket in Spain, containing STPP or other « upwelling areas » comprising only 0.1% of the ocean builders, used for washing textiles. 5 were conventional, surface, produce 50% of global fish production. This of which 3 contained STPP ; and 4 were compact, of clearly indicates a potential for increased production in which 2 contained STPP. marine ecosystems. Ail samples were subjected to a treatrnent reproducing a Maricult raises the question : « Cao we learn how nature typical European textile-washing process after which the creates these areas of high biological productivity, and are following parameters were measured we able to imitate this artificially in other coastal areas ? » The research programme emphasises studies of the effects (i) total suspended solids (TSS) of dosages of plant nutrients, namely nitrogen and (ii) dissolved organic carbon (DOC) phosphorus, at concentrations found naturally in upwelling (iii) chemical oxygen demand (COD) are as.

The experiments are to be conducted in areas of limited size in marine food webs and seaweed areas and involve The three main aims of the study were :- the supply of nutrients in controlled conditions : their aim (i) the experimental determination of chemical parameters being the defmition of the conditions leading to a useful related to the aquatic environment : it was found that productivity that cao be harvested the P-based formulations (both conventional and compact) contain less TSS, and have lower COD and Preliminary studies show that although introducing desired DOC than P-free formulations. Only P-based washing species on a large scale, plus other biological aimed powders irnproved washing performance in compact initiatives, was not enough, the introduction of fry would form ; moreover, a smaller amount of detergent was increase the chances of success if the fry's food supply needed for equivalent soil removal, implying a smaller increased correspondingly, particularly at the youngest release of the detergent into the aquatic environment. stages. This is only possible if an adequate amount of (ii) experimental determination of detergency for each nutrients is supplied by artificial upwelling or direct detergent category : common maximum soil removal application of mineral fertilisers was 40% on cotton and 48% on polyester/cotton. Nutrients will only be added where an increased Detergency on cotton fabric of 40% the calculated dose productivity of plankton is desired. The composition and was 8.8,10, 4.4, and 10.6g/L, for P-based conventional, the amounts must match both the fluxes which occur in P-free conventional, P-based compact, and P-free naturally high productive areas and the natural compact respectively. Similarly the dose was 11.9, 10, requirements, in order to prevent the growth of harrnful 4.2 and 10.6g/L, respectively on polyester/cotton. and undesirable algae.

2 SCIENTIFIC COMMITIEE ON PHOSPHATES SCOPE NEWSLETTER IN EUROPE

(iii) evaluation of the environmental impact at eliminated problems of precipitation and plugging in the equivalent detergency performance : as far as results of infiltration wells. For the fust time a phosphorus supply chemical loading to the environment is concerned, for the whole contaminated area was observed. assuming an equal detergency performance for a typical wash (20L), detergent load, surfactant load, Although ail the work to date on polyphosphates in bioremediation bas concentrated on tripolyphosphates, this COD, DOC and particularly TSS are much smaller for P-based than P-free detergents, especially P-based study showed the superiority of polyphosphate over compacts. orthophosphate on a field scale. It was also found that sodium hetamexaphosphate is superior over commonly After examining these three points it was concluded that used phosphates in transporting phosphorus over long the use of compact detergents containing STPP implies a aquifer distances. lower environmental impact than other detergents tested, Martin Steiof!Wolfgang Dott.Applied Bioremediation of in terms of both a reduced generation of sludge residues Petro/eum Hydrocarbons (30 1-309) and a reduced organic load in sewage works.

Comparative Study of Conventiona/ & Compact detergents. J.Sanchez Leal, L.Perez, J.Ribosa, M. T. Garcia & J.J. Gonzalez. Centro de lnvestigaci6n y Des arrollo (CJSC) Barce/ona, Spain. AUSTRALIA

JAOCS, Vo/.73, 27-30 no 1 (1996) ANALYSIS ON THE TOXICITY OF COMMERCIAL A V AILABLE LAUNDRY DETERGENTS ON NATIVE FRESHWATER CERIODAPHNIA DUBIA RICHARD GERMANY

Tests were carried out on 20 Australian, and 4 British BIOREMEDIATION OF AN OLD FUEL OIL­ laundry detergents , purchased in Sydney during June CONTAMINATED SITE USING 1994, to determine the relative impact of phosphate HE�TAPHOSPHATE containing and phosphate free formulations in view of the lack of knowledge on their toxilogical effects on the

Australian envi ronme nt. Groundwater is often found to be contaminated with The detergents were classified according to their chemical varions organic chemicals whereby heterotrophic composition using a 2 way classification system, whereby bacteria dominate. Phosphate is a required electron each product belonged to 2 categories :- acceptor, an essential nutrient, and an important limiting factor of hydrocarbon degradation in (HP), 5% · (i)high phosphate containing more than bioremediation. phosphorons on a weight to weight basis (w/w) (ii)low phosphate (LP) containing 1-5% phosphorons This case concerns contamination, 40-50 years ago, by (w/w) a leaking pipeline,of 15 000-17 000 L. Most of the oil (iii)phosphate free (PF) containing less than 1% noating on the groundwater was removed in the 70's ; phosphorons (w/w) the pollution now lies 4-9m below ground level. these categories were further subdivided into :­ The in situ remediation design consists of 2 infiltration (iv)containing neither enzymes nor zeolites (NoE & NoZ) wells, production wells, plus a groundwater processing (v) containing enzymes (E) plant. Before infiltration, hydrogen peroxide and nitrate (vi) containing zeolites (Z) were added to the reinfiltrated water to meet the electron (vii) containing enzymes & zeolites (E & Z) acceptor demand, plus phosphate to meet nutrient demand. Australian cladocera Ceriodaphnia dubia was chosen as Initial results suggested that phosphorus was the limiting the test species since it is representative of the factor for heterotrophic bacterial activity. lt is probable zooplankton which graze on algae and help prevent the that the phosphate stopped the limitation and oxygen was development of toxic algal blooms. cladocerans were used in and next to the infiltration wells. However, during exposed to 5 concentrations of each detergent, plus a the use of diphosphate, problems occured with the control, which were randomly placed in each test vessel precipitation of insoluable phosphate salts and thus and covered with cling film. Each treatrnent in each test plugging of the infiltration wells and the surrounding was triplicated and each test repeated 3 times. The tests aquifer occurred. were terrninated after 48 hours. A further quality control After 2 months the phosphorus source was stopped, the measure was taken using the Environment Canada methodology ( 1990) to determine if detergent toxicity data wells regenerated with H202 and acid, then 6 weeks later was replaced by sodium hexametaphosphate. This

3

Association Sans But Lucratif was accepted or rejected. Only data passing this test was used. NORWAY As far as the results are concerned it must be borne in mind that the percentage of the recommended dose (%RD) toxicity data were likely to contain greater error than the INPUTS TO THE OCEAN AND RESULTING concentration toxicity (mg!L) data since recommended POLITICAL DEMAND FROM THE SCIENTIFIC doses were often vague and it is questionable if COMMUNITY LEADS TO DESIGN OF A 3D consumers actualiy use these doses. MODEL It was found that the most toxic Australian detergent was approx. 35 & 25 (mg!L & %RD respectively ) times more toxic than the least toxic. The toxicity values obtained This paper describes a model to calculate mass and were similar to th ose deterrnined by Ankley et al ( 1990) volume transport and primary production throughout for U.S. detergents and individual surfactants tested on a the North Sea. This was the first time such a 3D U.S. cladoceran. baraclinic hydroclynamical model bad been coupled to a chemical biological model in order to better Ali 4 U.K. detergents were found to have medium toxicity understand these parameters. In response to political (1 mg!L

It was concluded that the explanation of the differences in toxicity was likely to lie in the chemical composition of In order to obtain realistic biological results, the coupled individual detergents. The important components chemical biological model system was based on a contributing to toxicity could include surfactants, enzymes sophisticated 3 dimensional physical model that was able and chelates. The second stage of this research project will to represent the vertical exchanges realistically. consider which of these components are predominantly responsible for the toxicity of Australian detergents.

Michael St. J. Warne. Australasian Journal of Exotoxicity This madel is discretized in a 20 x 20 km grid with 11 Vol!,pp 127-135, 1995 vertical layers which foliow the bottom topography. The madel calculates ali the P.C.B. prognostic variables every 15 minutes. It is strongly dependant on two physical constants:

a minimum value for the vertical eddy viscosity/diffusion coefficient

a dimensionless horizontal diffusion constant

The 7 chemica1 biological pragnostic variables are :

• inorganic nitrogen (such as nitrate and ammonia)

• inorganic phosphorus (phosphate)

• inorganic silicon (silicate)

• detritus (dead organic matter)

4 ------�

SCIENTIFIC COMMITTEE ON PHOSPHATES SCOPE NEWSLETTER

IN EUROPE

• diatoms nutrients to the North Sea, makes them a useful tool in political and environmental planning. • flagellates

• lightlturbidity Skogen, Svendsen, Bemstsen, Aksnes & U/vestad. 4 The compiling involves physical variables :- Esturine, Coastal and She/fScience (1995) 41, pp. 545- • subsurface light 565.

• hydrography

• the horizontal movement of water masses

• the vertical movement of water masses U.K.

The mode! is based on the following hypotheses

• nutrients are added to the system from the many rivers CLASSIFICATION AND ASSESSEMENT OF and from the atmosphere (only nitrate) WATER QUALITY IN LAKES

• nitrogen and phosphate are also reglemented from the dead algae, detritus at a constant rate This paper studies tbe way water quality can be • no zooplanktoon eating the algae and no <

• conductivity Blooms of toxic algae have dramatically increased over the past few years. The mode! was thus rerun based on • Secchi dise transparency political decisions to reduce nutrient input by 50% around • the North Sea, with the hypothesis of reducing initial pH conditions by the same percentage. • total alkalinity

• calcium ion concentration

This reduction only affected., as predicted (see above) the • total N concentration flagellates, with more than a 25% reduction in local regions, and an overall 5-10% reduction annually (with • winter total oxidised inorganic nitrogen ( effectively sorne uncertainties in the mode! due to Jack of resolution nitrate) concentration in the çoastal region). • total P concentration

• potential maximum cblorophyll a concentration However, the mode! can not be considered to be 100% • a score based on the nature of the submerged and accurate since various phenomenon can generate emergent plant community discrepancy in the simulation, eg. sensitivity of the model to initial conditions, annual calculation conception of the • the presence or absence of a fish community model, the importance of the recycling of nutrients, lack of one other sedimentationlresuspension process as a component of the The scheme is not, however, a closed and mode!. variables could be included wben necessary, and when appropria te reference data becomes available ( eg.oxygen profile, benthic invertebrate comrnunity, phytoplankton comrnunity and fish comrnunity). Despite these limitations the potential of using this kind of model, to study, for example, reduced deposition of

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Association Sans But Lucratif Standing waters are classified- within the scheme in a The Annual Agricultural Censuses allow reconstruction of value-or-state change system in wbicb the contemporary aspects of the water chemistry of appropriate baseline values of the variables are compared with a reference states for individual lakes or lakes grouped in uniform baseline state and then classified according to percentage regions. Appropriate nutrient variables (total N and total P ebange from this baseline. A mean percentage ebange in concentrations) can be predicted to within a few percent, ali variables can be calculated or the variables can be sub­ as can retention time and conductivity and from these grouped to indicate change in the directions of variables the others listed can be calculated. Comparisons eutrophication, acidification, infilling or potentially any of change can then be made for any contemporary data set. other factor if the relevant variables are included and can The scheme, incorp ting a ranking scheme for aquatic be determined in the baseline. The baseline state also ora plants, bas been designed for use on lakes grea ter than 2ha provides an objective reference for determining water in England and and for others of significant amenity quality objectives for given water bodies. Wales or conservation interest. It has been pre-tested on 90 lakes, the results showing a higb degree of change in British standing waters. Results are consistent with studies carried The baseline state is the one wbicb reflects a sustainable out with other methods. The system will be easy to agricultural land-use of the catchment and thus a computerise, allowing autornatic baseline calculations and consequent quality of the water body, determined by the comparisons. catchment's natural topography, clirnate and geology but in the absence of sewage effluent untreated to remove phosphorous. Since the Second World War land-use bas By Brian MOSS, Penny JOHNES and Geoffrey PHILLIPS. been increasingly determined by economie and Bio Rev. (1996) 71. pp 301-339 technological factors, with natural features taking second place.

The SCOPE Newsletter is produced by the SCIENTIFIC COMMIITEE ON PHOSPHATES IN EUROPE. a non commercial, non profit-making association (Association Sans But Lucratif) based in Brussels. The association includes international groups headquanered in Belgium, France, Spain, Sweden and the UK, producers of a wide variety of detergent ingredients including phosphates. lts aim is to provide a platform forobJective and sc1entific information on the effects of phosphate-containing and phosphate-free detergents on the environment. The SCOPE Newslctter is open to input from its readcrs across Europe and wc wc!come ali comments or mformation. Contributions from readers are invited on ali subjccts conccming phosphates, detergents, scwage treatment and the environ ment. Y ou arc invned to submit scientific papcrs for résumé, to send commentson the studies mentioncd in this Ncwslener or other scientific or technical news. For more information, pl case contact:/ E.C.U. (European Communications Unit)- who produce this Ncwslener for SCOPE- 20, rue de l'Arcade, 75008 Paris, France, Tel.+ 33 1 44 94 80 70 Fax +33 1 44 94 81 01 E-mail [email protected]

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6 J SCIENTIFIC COMMITTEE /"-- ON PHOSPHATES SCOPE NEWSLETTER IN EUROPE

NUMBER EIGHTEEN JULY 1996 v

THE NETHERLANDS 2· 2 However, no result on this issue coutd be obtained since no increase in P-concentration had appeared The effect of pollution on phytoplankton due to fish farming activities. The authors concluded dynamics in the River Meuse The correlation between phytoplankton that fish production could be multiplied by 200 without affecting the lakes' trophic condition. development, and chemical and physical characteristics of water extracted from the River Meuse has been examined. The River Meuse is GERMANY p. 4

- described as highly eutrophie and carrying a persistent load of toxic compounds. Results of the Opportunities and constraints in the study show that the phytoplanktongrowth rate may be recycling of nutrients related to a high toxicity. An approach incfuding both functional and structural parameters is recommended This article addresses the question of for rehabilitation programmes. nutrient recycling. Dr.Joachim Lammel, from the Centre for Plant Nutrition and Environmental FRANCE 2·2 Research in Hanninghof. Germany, studies the different components of the recycling nutrients issue (historical, sociological, and technical) . Evaluation of phosphorus from point economical sources on a catc hment area scale Researchers from the savoie region in France, have AUSTRALIA 2·5 proposee! a new mode! for evaluating phosphorus from point sources in a catchment area. The madel A new process reduces the amount and cost distinguishes phosphorus coming from the area itseH, of chemicals used for phosphorus removal sources coming from upstream, and diffuse sources. from waste water. The information collected from the application of the Alum sludge might contribute to lowering both cost mode! should contribute to developing and adjusting and amount of chemicals used for removing eutrophication control strategies in sensitive areas. phosphorus from waste water. If the trials conducted by the Centre for Wastewater Treatment at the NEW BOOK 2· 3 University of New South Wales at Bowral are successful, this technique could be used throughout Australia. Phosphorus in the global environment The Scientific Committee on Problems of the Environment (not to be confused with the NORWAY 2· 6 organisation SCOPE which edits this newsletter) publishes a compilation of articles on transfers, cycles Assessment of cost efficiency and and management of phosphorus in the environment. sustainability of wastewater treatment processes at the University of Trondheim. SWEDEN 2· 4 Cost efficiency and sustainability of different commonly used wastewater treatment techniques were evaluated. Results show that among the Impact of fish farming on lakes' phosphorus methods assessed, chemical treatment atone and concentration advanced treatment withchemical pre-treatment rank An extensive research project has been conducted in first with respect to criteria However, the author Sweden to evalua1e the impact of fish farms on bath notes that municipal wastewater treatment equipment eutrophication phenomenon in lakes (see also our is often chosen according to national or international previous Newsletter). One of the study's objectives treatment standards rather than the quality and self was to see whether phosphorus emissions from purifiCation capacityof the local receiving water. rainbow trout farms could be used to reduce mercury and radiocaesium levels in the lakes' fish.

SCOPE is a non-commercial, non-profit ma king European association based in Brussels. lts aim is to provide a platform for objective and scientific information on the effects of phosphate-containing and phosphate-free detergents on the environment.

SCOPE NEWSLETTER produced by European Communications Unit- 81, rue François Mermet- 69160 TASSIN - FRANCE -Tél. (33) 78 34 23 39

SCOPE : Scientific Committee on Phosphates in Europe -AssoCiation Sans But Lucratif sise à Bruxelles et soumise à la Loi du 27 juin 1921 '-

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ammonium concentrations are very high and cannat THE NETHER LANDS therefore be limiting in any part of the river. The hypothesis of a regulation by zooplanktongrazing has THE EFFECT OF POLLUTION ON also been considered. High zooplankton densities PHYTOPLANKTON DYNAMICS IN THE were correlated with declining phytoplankton RIVER MEUSE concentration in April, June and August.

ln water samples collected in locations with a high The correlation between phytoplankton content of organic substances, the low phytoplankton growth ratesupported the idea of a strong correlation development, and chemical and physical between the presence of toxicants and the inhibition characteristics of water extracted from the of plankton productivity. The presence in abundance River Meuse has been examined. The River of light and nutrients at these locations also upholds Meuse is described as highly eutrophie and this hypothesis. carrying a persis tent load of toxic compounds. Resulta of the study show that Due to uncertainties conceming the effiCiency of the the phytoplankton growth rate may be XAD-concentration procedure, the authors indicate related to a high toxicity. An approach ""· including both functional and structural that the interaction between organisms and pollutants may be under-estimated in the results. A possible para meters is recommended for impact of the pollutants on the plankton species rehabilitation programmes. composi1ion is also suggested. The River Meuse is described as a typical nutrient rich The authors question the current approach used in lowland river with relatively high plankton productivity. remediai policies which focuses on single target Previous studies have shawn a strong relationship groupsof poHuters and individual marker substances. between the presence of toxicants and the decline of Such an approach does not consider the interactions species in the river. between species and the possible combined effect of chemical, physical and biological parameters affecting Twenty litre water samples were collected at 8 points aquatic ecosystems. along the river in February, April, June, August, October and December 1993. The samples were D.M.J. TUBBING, D. DE ZWART AND T. BURGER­ taken to a laboratory where they were maintained at WIERSMA, (1995) Phytoplankton Dynamics in the their original temperature. The following parameters River Meuse as Affected by Pollution, in The were measured : Netherlands Journal of Aquatic EcoJogy, 29(1), pp. 103-116. Biological parameters:

Chlorophyll A concentration Contribution of functional groups to FRANCE Chloropyll A Rate of carbon fixation by phytoplankton EVALUATION OF PHOSPHORUS Bacterialgrowth FROM POINT SOURCES ON A CATCHMENT AR EA SCALE Physicaland chemicalparameters:

Researchers from the Savoie region in Dryweight of suspended matter France, have proposed a new model for Dissolved reactive phosphate evaluating phosphorus from point sources Ammonium ions in a cat chment area. The model Nitrate distinguishes phosphorus coming from the Nitrite area itself, sources coming from upstream, Dissolved reactivesilicate and diffuse sources. The information collected from the Toxicity of polar organic compounds concentrated application of the model should contribute by XAD resinand measured with the Microtox test to developing and adjusting eutrophication system. control strategies in sensitive areas.

The study revealed a relatively law Chlorophyll A concentration in the River Meuse in comparison wi1h lt is diffteult, because of the costsinvotved, to produce other large rivers. This observation cannot be a reliable evaluation of point sources of phosphorus explained by nutrient depletion. Phosphate and for a large area by measuring the flow from each

2

-·----- •, SCIENTIFIC COMMITIEE r ON PHOSPHATES SCOPE NEWSLETTER

IN EUROPE

source. The rate of transfer of P originating from The Scientific Committee on Problems of upstream is also hard to predict since it depends the Environment (not to be confused with widely on the hydrofogicaland climatic conditions. the organisation SCOPE which edits this newsletter) publishes a compilation of Because of these difficulties, a team from INRA articles on transfers, cycles a nd (Institut National de Recherche Agronomique) in management of phosphorus in the Thonon, Savoie, France have developed a mode! environment . which aims at evaluating point sources by measuring the P released during droughts, when point sources Phosphorus in the Global Environment is the arelikely to be the predominant input of P into rivers achievement of a major study launched by the and soluble P represents90% of total P. Scientifte Committee on Problems of the Environment in 1987. lts objective was to improve the Severa! conditions are necessary to guarantee the understanding of •phosphorus cycles in terrestrial and efficacy of the approach, such as a detailed aquatic ecosystems". Data and research presented knowledge of the hydrology of the catchment area during four regional workshops by 240 scientists were and of the variabitity of the P input to the river. ln summarised during a final workshop hetd in Hungary in addition, sampling must be done out of flooding 1993. periods since phosphorus reaches the sediment, whereit forms an important reservoir of P, likely to be We quote below a summary of this highly detailed reteased during floods. volume as published by the editer:

During droughts, point sources represent the only "Phosphorus is one of the world's vital but retatively significant input of P into the area and their volume is scarce resources, which is a limiting factor in plant (and constant, regardless of the hydrotogical and climatic therefore food and fibre) production. This volume conditions. ln contrast, the volume of diffuse P brings together data and concepts on the transfer and exported from the area varies with the flow of water. transformations of phosphorus. Whenthe waterflow increases, the amount of P tends to increase likewise until it reaches a constant value. Although the phrase "biogeochemical cycle• is Whenthis threshold is reached, inputs equal outputs commonly used to describe the tate of elements of and a reliabtemeasure of P from point sources can be the environment, it has become apparent that for taken. phosphorus, linear transfers from land to rivers to lakes and seas are more typical. ln sorne regions, This method was tested in the Foron catchment areas, these transfers are augmented by the addition of a tributary of the Geneva Lake. Weekly figures were mined phosphates and manure, and surplus considered to be the most reliable since phosphate needs to be managed with care. concentrations of P from point sources varies hourty Environmental managers need to incorporate an and daily. For an areacovering 56, 9 km2, the average understanding of phosphorus transfers into their weekly output of P was estimated at 90 kg. decision making.

The authorsconsider that this approach is applicable But the contrais on phosphorus transfers through to areas with a surface less than 100 J

TIESSEN, H. (1995) Phosphorus in the Global NEW BOOK Environment; Transters, Cycles and Management, in SCOPE n°54, pp460,published by John Wiley & PHOSPHORUS IN THE GLOBAL Sons, Chichester. ENVIRONMENT * reproduced with the authorisation of the publisher. Transfers, Cycles and Management

3

Association Sans But Lucratif The authors conclude that environmental authorities SWEDEN shoutd review their methods for evaluation of the impact of fish farming on lakes' eutrophication. ln IMPACT OF FISH FARMING ON LAKES' addition, they suggestedthat the tonnage presently PHOSPHORUS CONCENTRATION allowed by farming permits could be raised from 50 tonslyear to 10, 500 tonslyear without affecting the lakes. An extensive research project has been HAKANSON, L, CARLSSON, L., JOHANSSON, T. conducted in Sweden to evaluate the impact (1995) Gan emissions from fish farms be used as a of fish farms on eutrophication phenomene remedia/measure for lakes? in Vatten 51: pp 112-124, in lakes (see also our previous Newsletter). Lund (in Swedish.) One of the study's objectives was to see whether phosphorus emissions from rainbow trout farms could be used to reduce mercury and radiocaesium levels in the takes' fish. GERMANY

However, no result on this issue could be OPPORTUNITIES AND CONSTRAINTS IN obtained since no increase in P­ THE RECYCLING OF NUTRIENTS concentration had appeared due to fish farming activities. The authors concluded that fish production could be muttiplied by This article addresses the question of 200 without affecting the lakes' trophic nutrient recycling. Dr. Joachim Lammel, from condition. the Centre for Plant Nutrition and Environmental Research in Hanninghof, Germany, studies the different components As part of an extensive study on eutrophication of the recycling nutrients issue (historical, phenomenon in Swectish lakes, a group of scientists sociological, economical and technical) at the Uppsala University studied the pôssibility of Several approaches are discussed, using phosphorus emissions from fish farmsas a way particularly:

of reducing the high levels of mercury and • Nutrient use and cycling in agriculture

radiocesium present in the lakes' wild fish {the theory • Demand from society for recyling nutrients

of "biological dilution.") This hypothesis could not be • Recycling of manure

verified since the expected rise in total P­ • Recycling of urban waste

concentration did not occur. • Recycling and the fertiliser industry Conclusions of previous studies had shown that this lack of correlation between fish farming and P· With the development of intensive farming the concentration cannot be explained by climate traclitional nutrient cycfing practices on-farm are no conditions, precipitation or by the hydrology and the longer appropriate. ln Europe the boom of mineral chemistry of the lakes. lnsteacl, the reasons likely to fertilisers means that we can now supply growing explain these results were: urban populations, and has broken down traditional nutrientcycling practices. ln order to restore the cycle the uptake of P from trout faeces by wild fish nutrients need to be used and recycled efficiently. At (mainly bream androach), the sarnetime, in many developing countries, mineral the elimination of phosphorus from the fish feed ferblisers are necessary to restore nutrient cycling in by bioproduction directly followed by depleted soils. sedimentation, predation through the food chain and transter downstream. Due to intensive livestock farming, manure is now the main source of nutrients available for recycling, and Data has also shown that no significant primary surpluses are becoming increasingly frequent. The production resulted from the activities of the fish efficient management of this source of nutrients is farrns, which seems to indicate that direct uptake of now the challenge for livestock farmers, particularly in phosphate from the lakes by wild fish was very the light of possible proposed legislation limiting the substantial. use of minerar fertilisers.

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------SCIENTIFIC COMMITIEE ,- ON PHOSPHATES SCOPE NEWSLETTER

IN EUROPE

Despite growing public opinion to limit the use of technique considered expensive for small and landfill sitesthe application of urban waste to farmland mediumsize wastewaterworks. is not recommended because of the potential content of heavy metals and other harmful Australian Environmental Review (December95) Vol. substances, unless separate collection of organic 10, n°11:p.13 waste is implemented. This, however, represents substantial extra costs which may be justified by sustainable arguments such as the saving of landfilf space, or recycling of finite resources {eg. NORWAY phosphate). ASSESSMENT OF COST EFFICIENCY AND The fertiliser industry is the last key element in this SUSTAINABILITY OF WASTE WATER process, as it consumes lïmited resources, such as TREATMENT PROCESSES phosphorus extracted from rock and energy from fossil fuels. tts ïnvolvement in the coming debate between farmers and policy makers will finally contribute to closing the nutrient cycle again. Cost efficiency and sustainability of different commonly used waste water LAMMEL, J. (1995) Opportunities and Constraint in treatment techniques were evaluated. the Recycling of Nutrients, paper presented at the Results show that among the methods International Conference in Cambridge, organised by assessed, chemical treatment alone and The Fertiliser Society, Proceedings N°372, advanced treatment with chemical pr• Peterborough. treatment rank first with respect to both criteria. The author notes that municipal waste water treatment equipment is often chosen according to national or AUSTRALIA international treatment standards rather than the quality and self purification A NEW PROCESS REDUCES THE AMOUNT capacity of the local receiving water. AND COST OF CHEMICALS USED FOR PHOSPHORUS REMOVAL The evaluation was based on a treatment plant FROM WASTE WATER. designedfor serving a population of 100 000 people. Five differenttre atment process were examined:

Alum sludge might contribute to lowering Primary(mechan ical) treatment both cost and amount of chemicals used for Secondary (high load biological or chemical) removing phosphorus from waste water. If treatment the trials conducted by the Centre for Advanced secondary with nitrification -- Wastewater Treatment at the University of (mechanicallbiologicalor chemicaJJbiological) New South Wales at Bowral are successful, Tertiary treatment (mech./biol./chem. or this technique could be used throughout chem.lbiol.) Australia. Advanced tertiary treatment including nitrogen removal (mech.lbiol./chem., chem.lbiol. or Alum is normally usedas a coagulant in drinking water mech.lbiol.) treatment . This proœssgener ates a by-product, alum sludge, which is left to dry in a pond before going to The cost of the treatment increases with the landfill. sophistication of the technology, which in turn depends on the type of component removed from The idea promoted by the Department of Land and waste water. Therefore, the cost efficiency was Water Conservation and the Co-operative Research cafculated for each single component. For example, Centre for Wast.e Management and Pollution Control secondary treatment and primary precipitation were consists of reintroducing to waste water the alum the most cost efficient techniques with respect to sludge from previous treatment. BOD and suspended solids removal respectively. ln tum, chemical treatment by primary precipitation was The main advantage of the alum re-useprocess which found to have the best ratio for phosphorus removal. uses the same product twice is a reduction of the Different possible situations were also considered amount of chemicals used in the chemical recovery withrespect to the impact of sewage water discharge processes. This technique is also reported to be more on receiving waters. A costJimpact ratio was cafculated cast-efficient than Biological Nutrient Removal, a using the oxvgen consumption potential of each componentas weil as the likely impact of P and N on

5

Association Sans But Lucratif " l ,.·,

algal growth, under both marine and fresh water biological treatment. The LCA indicator is also conditions. favourable to direct chemical treatment. The study also showed that using the biogas resulting from Two methodologies were used to assess the sludge digestion also represents a viable way to sustainability of each process: increasethe treatment sustainability.

the energy and raw material consumption vs each The author concludes that water treatment process' potential to reduce oxygen consumption technologies should be selected in the light of in receiving waters costlbenefit criteria. He regrets that "such analyses the lite cycle assessment (LCA) technique, using are rarely carried out and that suitable tools for such the SimaPro mode!. evaluations are lacking". Acknowledgingthe limits of a study presented as an attempt to show a direction for The results show that direct chemical treatment has a developing evaluation methods", the author better ratio with respect to cost/efficiency, oost/impact recommends that more work be done on developing a and energy consumptionlimpact when compared to reliable mode! for calculating the . impact under different receiving water conditions.

0DEGAARD, H. (1995) An evaluation of cost efficiency and sustainability of different waste water treatmentprocesse s. in Vatten 51:291-299, Lund.

The SCOPE Newsletter is produced by the SCIENTIHC COMMITfEE ON PHOSPHATES IN EUROPE, a non commercial, non profit-making association (hsodation Sans But Lucratif) based in Brussels.

The association includes international groups headquartered in Belgium, France, Spain, Sweden and the UK, producers of a wide variety of detergent ingredients including phosphates. Its aim is to provide a platform for objective and sdenttific information on the effects of phosphate-containing and phosphate-free detergents on the environment.

The SCOPE Newsletter is open to input from its readers across Europe and we welcome ail comments or information. Contributions from readers are in"Vited on all subjects concerning phosphates, detergents, sewage treatment and the environment. You are invited to submit sdentific papers for résumé, to send comments on the studies mentioned in this Newslener or other sdentific or technical news.

For more information, please contact: E.C.U. (European Communications Unit)- who produce this Newsletter for SCOPE - 20, rue de l'Arcade, 75008 Paris, France, Tel.+ 33 1 44 94 80 70 Fax +33 1 44 94 81 01 E-mail [email protected]

The SCOPE NEWSLE'ITER is also available on INTERNET at: http://www .asi.fr/scope

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------···- SCIENTIFIC .'"'-� COMMITTEE ON PHOSPHATES SCOPE NEWSLETTER IN EUROPE

NUMBER SEVENTEEN APRIL 1996

UNITED KINGDOM �.2 SWEDEN �.5

Carp appear to be a major cause of Flows and effects of phosphorus in a eutrophication in Engllsh sites of lake - calibrations and simulations special scientiflc lnterest using the LEEDS model Eutrophie status and symptoms of eutrophication of The LEEDS model (Lake Eutrophication, Effect­

_ 1 02 Sites of Special Scientific Inter est in England Dose-Sensitivity model) was used to evaluate the were examined. Eighty four showed symptoms of actual impact of fish-farming on Lake Bullaren, eutrophication, a phenomenon attributed primarily to Sweden. After calibrating, the multi-criteria model sewage effluent, carp and bream. was used to predict the maximum volume of phytoplankton likely to result from the input and circulation of phosphorus. lt appears that a significant SWITZERLAND �.2 part of the variability is related to internai dynamic processes and that over-simplistic models such as The state of Swiss lakes vollenweider or OECD-type can give totally The Swiss Federal Office for the Environment, meaningless predictions. Forests and Landscape published a review of the environmental state of the country's 20 most THE NETHERLANDS 6 important lakes. �.

Selection mechanisms controlling FIN LAND �.3 blomass distribution Water, Science & Technology published a Impact of EDTA on toxicity of metals compilation of the papers presented in a conference We publish here below the full text of a letter on Selection Mechanisms Controlling Biomass submitted to SCOPE Newsletter. lt presents the Distribution between Cyanobacteria, Phytoplankton results of a study conducted to evaluate the impact and Macrophytes Species, held in Noordwijkerhout, -- of metal complexation by EDT A on toxicity on The Netherlands, in December 1994. Photobacterium phosphoreum.

CANADA �.6 FINLAND �.4 Autumn leaves gathering in urban Factors influencing the service life areas may contribute to of home appliances eutrophication A study was conducted in Finland for the Consumer Leaves piled up along roadsides in urban centres Affair Bureau of the Ministry of Trade and lndustry in may contribute to up to 5 % of the total export of order to assess the factors influencing the service life phosphorus from urban catchment. Prompt leaf of home appliances. As for laundry and dish washing pickup is recommended in order to prevent machines, it appears that phosphate free-detergents aggravation of eutrophication phenomenon. are responsible for a greater amount of deposit accumulation in the machines than phosphate containing products.

SC OPE is a non-commercial, non-profit ma king European association based in Brussels. lts aim is to provide a platform for objective and scientific information on the effects of phosphate·containing and phosphate·free detergents on the environment.

SCOPE NEWSLETIER fJroduced by European Communications Unit- 81, rue François Mermet- 69160 TASSIN - FRANCE -Tél. (33) 78 34 23 39

SCOPE : Scientific Committee on Phosphates in Europe ·Association Sans But Lucratif sise à Bruxelles et soumise à la Loi du 27 juin 1921 observed. lt is only the presence of large carp UNITED KINGDOM (Cyprinus carpio) which could explain the appearance of eutrophication problems. CARP APPEAR TO BE A MAJOR CAUSE OF EUTROPHICATION IN ENGLISH SITES ln sorne sites, the additional presence of bream (Abramis brama) also contributed to the OF SPECIAL SCIENTIFIC INTEREST phenomenon. Apart from the feeding in the sediment, this last species is known tor feeding on zooplankton during the first year of lite, which has a direct impact on phytoplankton grazing and Eutrophie status and symptoms of regulation. eutrophicat ion of 102 Sites of Special Sc ient ific lnterest in England were The symptoms of deterioration were observed mainly examined. Eighty four showed symptoms of among the plant communities. The authors mention, eutrophication, a phenomenon attributed however, that this may simply be due to the tact that primarily to sewage effluent, carp and plants are more frequently monitored than animal bream. communities.

The authors recommend that : The concept of Site of Special Scientific lnterest (SSSI) was initiated by English Nature in order to sewage effluent be diverted or treated with allow a better understanding and assessment of phosphate removal in at least30 cases, state and degree of changes of aquatic sites of biomanipulative measures including carp removal particular importance. After collecting data from be implemented in 18 cases, English Nature, the National River Authority, British systematic monitoring of SSSis for the effect of Waterways, water supply companies and field eutrophication be carried out. sampling, the study went on to examine the trophic state and eutrophication symptoms of 1 02 selected SSSis. L. Carvalho, B. Moss, The current status of a sample of English Sites of Special Scientific lnterest subject Of ali these sites, 84 % showed symptoms of to eutrophication. in Aquatic Conservation: Marine eutrophication. The occurence of this phenomenon and Freshwater Ecosystems, Vol. 5, 191-204, 1995. had changed the conservation interest of the site in 69 cases.

Table 1. Numberof SSSis showin omsof OEGDGategory Numbêrof �s eutro�WcationSS sWHh examined symptomsof

Ohgotroptîtc � eulr�ication SWITZERLAND tv'esotrophtc 13 9 Eutrophie 13 10 Hypertrophie ffi 57 THE ST ATE OF SWISS LAKES 9 9 UnknownTotal 102 85

The Sw iss Fe deral Office for the Among the 85 sites affected, untreated sewage Environment, Forests and Landscape effluent discharge was identified as the primary publlshed a re view of the environmental cause of eutrophication in 35 cases, and possibly in state of the country's 20 most Important 5 additional cases. The second most important cause lakes. was the presence of certain tish , mainly common carp and common bream. This document is devided into 3 parts, one containing a review of basiclimnology principles, one These species search for food in the sediment. ln so addressing the question of waste water treatment, doing, they mobilise nutrients and increase the water protection and rehabilitation of lakes and the last one body's turbidity. ln fifteen cases, external nutrient presenting the 20 lakes, with respect to their load appeared unlikely to lead to the symptoms environmental status.

2 SCIENTIFIC COMMITTEE ON PHOSPHATES SCOPE NEWSLETTER

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The chapter on limnology devotes a large part to the complete mixing of the lake water is very unlikely question of thermal exchanges, lake stratification and to happen due to the lakes' morphology, major to the role of nutrients. As an illustration of the climatic change could provoke this mixing and complexity of these processes, the report describes increase the presence of nutrients in the how excessive consumption of oxygen from deep phototrophic layer. waters. due to enhanced primary production in surface layers, can trigger chemical reactions in the sediment which, in turn, provokes an important Very heavily loaded lakes with a phosphorus release of phosphorus. concentration between 90 to 140JJgP/I. They belong to areas with a very high population The report discusses protection and remediation concentration or intensive farming. ln this last measures applied in Switzerland. Phosphorus case, it is very unlikely that the lakes will rapidly removal from waste water by simultaneous move towards the second group. precipitation was made mandatory in ali waste water treatment (WWT) plants of lakes catchment areas in As a conclusion, the authors consider that the 1971. Sorne WWT plants located in the most environmental status of the Swiss lakes has greatly sensitive areas are eq uipped with improved since the seventies but acknowledge that - flocculationffiltration systems which allow a 90% P reduction measures did not always reach the set phosphate recovery efficiency. objectives. Agriculture is now considered the major source of pollution. They also warn about the likely The report indicates that the amount of phosphorus adverse consequences of a long term warming of the in domestic waste water before treatment was lakes' temperatures. reduced by 30% after the introduction of a detergent phosphate ban in 1986. Office Fédéral de l'Environnement, des Forêts et du Paysage, L'Etat des Lacs Suisses, Cahier de l'Environnement no 237, Berne, 1994. Despite the measures implemented, it is concluded that, because of the high amounts of P present in the sediment, a return to the "natural" state is often impossible by simply reducing the nutrient input to the lakes, even when conditions are favourable. ln most cases, internai measures such as deep water FINLAN D recirculation, introduction of low nutrient containing water and oxygenation are necessary to prevent P IMPACT OF EDTA ON TOXICITY OF release from the lake beds. METALS

The Swiss lakes are divided into 3 groups:

Oligotrophic lakes with a phosphorus We publish here below the full text of a concentration between 3 and 30t�QPII. At these letter submitted to SCOPE Newsletter. lt concentrations, the oxygen present in deep presents the results of a study conducted waters and sediment is abundant enough to to evaluate the impact of metal effectively transfer P from water to the sediment. complexation by EDTA on toxicity on Photobacterium phosphoreum.

Lakes with a medium to heavy P load, with a concentration between 30 and 60JJgP/I. Among a number of industrial applications, P concentrations in these lakes have been Ethylenedimineacetic acid (EDTA) is used as an decreasing due to remediai measures in their additive to substitute for polyphosphate in cleaning catchment areas. formulations. ln external waste treatment, it is known for having a low reduction capacity and for increasing Lake Leman and Zurich belong to this group. heavy metal concentration in waste water effluents Their upper layer of water, where primary by forming cyclic, water-soluble chelates with metal production occurs, is low in phosphorus content ions. Thus, a high percentage of EDT A is released when compared to the lowest layer. Although a into natural waters.

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Association Sans But Lucratif As a nitrogen containing compound, EDTA might As for laundry and dish washing machines, constitute a source of nutrient for aquatic algae lt appears that phosphate free-detergents under certain circumstances. EDTA also increases are responsible for a greater amount of general permeability, releasing calcium ions from cell deposit accumulation in the machines than membranes. phosphate containing products.

The presence of EDT A was monitored in pristine waters of Central Europe. Concentrations between The trial involving the comparison of phosphate­ 1-80 pg/1 were found, which are not likely to cause containing and phosphate-free detergent started acute taxie effects. On the ether hand very little is after a questionnaire distributed to appliance known of the long-term toxicity of EDT A. repairmen revealed that faults in washing machines had increased after the introduction of phosphate­ ln this study, the toxicity of several heavy metals was free products. investigated after complexation by EDTA. Microtox bioassay, based on measuring the bioluminescence The tests were conducted in 4 separate districts of Photobacterium phosphoreum, was used as an corresponding to water hardnesses ranging from indication of toxicity. The reproducibility of data 2°dH to 7°dH. Two hundred washes were done, revealed correlation coefficients between O. 983- which corresponds to a year's use. The assessment 1.000. of the impact on washing machines was performed by a service expert group, in the presence of The results suggest that complexation by this representatives of detergent companies. chelating agent increases the toxicity of iron, has very low or no influence on the toxicity of Cu, Cd and The trials showed that the use of P-free detergents Hg, and reduces noticeably the toxicity of Zn and Pb. increases the level of encrustation on beth dish and The slopes of the dose-response curves were laundry washing machines. steeper for metal complexes than for metals, suggesting that toxicity mechanisms change during Furthermore, with dishwashers, a film was formed on complexation. the surface of the dishes when P-free detergents were used. This did not occur with phosphate The inhibitory effect of EDT A on metal toxicity is containing brands. explained by the binding of the reactive sites of heavy metal ions, thus preventing their normal As for laundry washing machines, tests showed a action. slightly higher in-machine deposition with P-free products but the difference with P-containing cnes Mika Sillanpaa, Letter submitted to SCOPE was not as marked as for dishwashers. The most NEWSLETTER, Laboratory of lnorganic and obvious precipitation appeared in the drain hose. Analytical Chemistry , Helsinki University of Technology, January 1996. lt is stated that more tests are needed to reach a final conclusion since only one kind of washing machine was used and a limited number of detergents were tested. However, these results clearly suggest that beth the type of builder and the water hardness FINLAND influence the number of problems in washing machines and dishwashers. FACTORS INFLUENCING THE SERVICE LIFE OF HOME APPLIANCES A Reisbacka, A Rytkonen, Factors influencinq the service /ife of home appliances, work carried out by the Working Efficiency lnstitute (Fin/and) for the A study was conducted in Finland for the Ministry of Trade and lndustry, TTS-Jnstitutes Consumer Affair Bureau of the Ministry of publication 34111995, ISBN 951-788-3, 245 p., Trade and lndustry in order to assess the 1995. factors influencing the service life of home appliances.

4 SCIENTIFIC COMMITIEE ON PHOSPHATES SCOPE NEWSLETTER

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a new format for environmental SWEDEN consequences analysis, with special attention to the volume of phytoplankton FLOWS AND EFFECTS OF PHOSPHO RUS and extreme climatic conditions, IN A LAKE - CALIBRATIONS AND SIMULATIONS USING THE LEEDS MODEL a better understanding of the processes regulating recovery after an hypothetical extreme eutrophication.

The LEEDS model (Lake Eutrophication, Effect-Dose-Sensltlvity model) was used to Among the results of the study, it appears that: evaluate the actual Impact of fish-farming on Lake Bullaren, Sweden. After 5 % callbrating, the multi-criteria model was About of the P contained in the used to predict the maximum volume of active surface of the sediment - which 90% phytoplankton likely to result from the accounts for of the P in the lake - is transported each year to the productive input and circulation of phosphorus. lt appears that a slgniflcant part of the surfacewaters. variabillty is related to Internai dynamic Of processes and that slmplistic modela auch the three primary phosphorus inputs, 72% as Vollenweider or OECD-type can give cornes from the in-flowing waters (natural P-flow and agriculture), 25% from totally meaningless predictions. the fish farm and the remairiing 3% from the rain. Lake Bullaren is in the middle of a controversy related to the possible impact of fish farming on the trophic The exchange of phosphorus through statusof the lake. The LEEDS model is presented as sedimentation, resuspension and "time dependent, generic-dynamic model which diffusion is very extensive. The P flow accounts for ali major processes regulating the from the sediment corresponds to almost distribution and effects of phosphorus in lakes. half the total weight of P externat input.

Lake Bullaren could probably tolerate a ln order to calibrate the model, data were gathered 1 000 on amounts, fluxes and concentrations of fish production of tons a year, 70 phosphorus in the lake. From this step on, white the present permit allows only predictions of the maximum volume of phytoplankton t/year. (target effect variable) were made on a monthly basis.

Dissolved and particulate P, stratification, tt is suggested that the controversy surrounding fish sedimentation, re-suspension/advection, diffusion, farming activities on Lake Bullaren are based on an bioturbation, predation, fishing, mixing and over-simplistic understanding of phytoplankton regulation phenomenon derived from the application mineralisation are among the parameters accounted for by the LEEDS model, as weil as the different P of models such as Vollenweider or OECD-types, sources feeding the lake. qualified as very crude and not adapted to a case like Lake Bullaren.

The study focused primarily on providing: L. Hakanson, L. Carlsson, Flows and effects of the quantification of internal loading, phosphorus- Calibration and simulations usinq the LEEDS-mode/ in Lake Bullaren, Sweden, Vatten 51, a phosphorus budget (amounts and 183-218, Lund 1995. fluxes),

indications on the effects of seasonal variations on the input of P,

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Association Sans But Lucratif L.R.Mur, P.M. Visser and H. Reith, Selection THE NETHERLANDS Mechanisms Controllinq Biomass Distribution. introductorypaper by C. Reynolds, in Water Science SELECTION MECHANISMS CONTROLLING & Technology, Vol. 32, N°4, 1995. BIOMASS DISTRIBUTION

Water, Sc ience & Technology publlshed a compilation of the papers presented in a CANADA conference on Selection Mechanlsms Controlling Biomass Distribution between AUTUMN LEAVES GATHERING IN UR BAN Cyanobacteria, Phytoplankton and AREAS MAY CONTRIBUTE TO Macrophyt es Species, held in EUTR OPHICATION Noordwijkerhout, The Netherlands, in December 1994.

Leaves plled up along roadsides in urban This conference paid particular attention to the centres may contribute to up to 5 % of the changes occurring in the phototrophic compartment total export of phosphorus from urban of aquatic ecosystems. The conference was catchment. Prompt leaf pickup is organised by the International Association for Water recommended in order to. prevent Quality and the International Association of aggravation of eutrophication Theoretical and Applied Limnology. ln total, 82 phenomenon. scientists from 19 countries participated in this conference. Laboratory experiments were conducted by the 37 5 papers were presented covering separate Department of Biology at McGill University, Montreal, fields: to evaluate the amount of phosphorus exported by water leaching through birch and trembling aspen Light Climate and Hydrodynamics leaves. Nutrients Physical and Chemical Factors ln southern Canada, plant litter represents from 200 Biological Interactions to 800g/m2, a possibly significant nutrient supply to Physical, Chemical and Biological Interactions. receiving waters. The amount of P exported to gutters and rivers can be substantial depending on The conference confirmed that the mechanisms of the length of the period between leaf gathering and the major ecological factors influencing competition pickup. and succession are weil known and that the understanding of the contribution of each factor is The objective of this study was to assess the amount rapidly growing. of total phosphorus released per g of dried and non­ dried leaves placed in flasks containing distilled The conference has also demonstrated that water. strategies focused on reduction of external nutrient alone are often not sufficient enough to restore Analysis of samples extracted from the flasks after eutrophied waters and that an integrated approach is one week showed a strong linear relation between P necessary. release and leaf mass. Based on average litter fall in southern Canada, it is estimated that fallen leaves ln this approach, biological and physicochemical can contribute 11 to 45 mg of total P per m2, which factors must be accounted for in order to enable represents up to 5% of the total export of total P from more balanced water management practices. urban areas. Stronger co-operation between technologists and biologists is also recommended. No significant difference was observed between total P concentrations of samples from dried and non­ dried leaves.

6 SCIENT! FIC COMMITIEE ON PHOSPHATES SCOPE NEWSLETTER

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H. Guibert, R. France, Laboratory Prediction of Phosphorus Release from Deciduous Leaves to Urban Runoff, Water Quality Res. J. Canada, Vol. 30, N°2, 243-246, 1995.

The SCOPE Newsletter is produced by the SCIENTIFIC COMMITTEE ON PHOSPHATES IN EUROPE, a non commercial, non proflt­ maklng association (Association Sans But Lucratif) based in Brussels.

The11SS0Ciation lncludes international groups headquartered in Belgium, France, Spain, Sweden and the UK, producers of a wlde variety of detergent ingredients including phosphates. lts aim ls to provide a platform for objective and sclentifiC Information on the effects of phosphate-containing and phosphate-free detergents on the environment.

The SCOPE Newsletter is open to input from its readers across Europe and we welcome ali comments or information. Contributions from readers are invited on ali subjects conceming phosphates, detergents, sewage treatment and the environment. Vou are invited to submit scientifiC papers for résumé, to send comments on the studies mentioned in this Newsletter or other scientifiC or

technical news.

For each study or paper mentioned in the SCOPE Newsletter, the full document can be obtained directly from:

E.C.U. (European Communications Unit)- who produce this Newsletter for SCOPE- 81, rueFranÇOis Mermet- 69160 TASSIN France- Tél: (33) 78.34.23.39- Fax: (33) 78. 34. 83. 49

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Association Sans But Lucratif ���- �------����rrrrlf�------C C S IE NTi Fi COMMITTEE ON PHOSPHATES SCOPE NEWSLETTER

IN EUROPE Number Sixteen No vernber 1995

SC ANDINAVI A p.2 This statement was made in a report published by VA-FORSK, a research programme managed by VAV, the Swedish Revision Of The Nordic Environmental Water Association. The report is entitled: Label Laundry detergents: Effects on waste water treatment and the environment, Three years after the adoption of its first version, the revised Nordic Swan Label is more severe on most detergents' UNITED KINGDOM p.S components, but reverses its earlier position on phosphates. Completely excluded in the Phosphates Used To Restore Acidified 1992 version, phosphate containing Lakes detergents can now apply for and obtain the Nordic environmental label. Tests conducted by researchers at the lnstitute of Freshwater Ecology and Lancaster University reveal that phosphates can be used to control lake acidity. SWEDEN p.3

FRANCE & SWITZERLAND �.6 Swedish Water Treatment Experts Compare Phosphate-Based And Evolution Of Phosphorus And Biomass Phosphate-Free Products Concentration ln Lake Geneva.

"The use of phosphate based detergents Both phosphorus and biomass concentrations means lower organic loading, lower decreased in 1994. Biomass concentration ecotoxicity to micro organisms, lower still remains higher than values recorded from concentration of suspended solids and a 1989 to 1991. The International Commission lower oxygen consumption in municipal for the Protection of the Leman Waters sewage treatment plant"- (CIPEL) announces that 87 % of the· population of the lake's catchment area is now connected to waste water treatment plants.

SCOPE 1s a non-commercial, non-profit making European association based m Brussels.

lts aim 1s to provide a platform for objective and sc1ent1fic mformat1on on the effects of phosphate-contaming and phosphate-free detergents on the environment SCOPE NEWSLETTER

produced by European Communications Unit- 81, rue François Mermet- 69160 TASSIN - FRANCE -Tél. (33) 78 34 23 39

SCOPE : Scientific Committee on Phosphates in Europe -Association Sans But Lucratif sise à Bruxelles et soumise à la Loi du 27 juin 1921

------.

�

SCAN DINAVIA The two other environmental labels used in scandinavia also allow a certain amount of

REVISION OF THE NORDIC phosphate in detergents. ENVIRONMENTAL LABEL The new criteria for household laundry detergents cover more parameters and ali the ingredients are assessed. The volume of zeolites, a phosphate substitute, is now taken Three years after the adoption of its into account. first version, the revised Nordic Swan Label is more severe on most Requirements on dosage and efficiency are detergents' components, but reverses also established. The Swedish National its earlier position on phosphates. Board for Consumer Policies produced a test Completely excluded in the 1992 method for measuring washing efficiency at version, phosphate containing the recommended dosage. detergents can now apply for and obtain the Nordic environmental label.

Phosphates reassessed

After the revision of the Nordic environmental "We have reassessed the issue of label, applicable in the Spring of 1996, only phosphates", sa ys Magnus Hedenmark, eco­ about half the products already labelled will toxicologist at SIS. This assessment led to pass the new criteria. the decision that " a detergent can have the Swan ecolabel and contain a certain amount To the Swedish Standards Institution of phosphate". (Standardiseringen i Sverige - SIS), which is responsible for developing the Nordic Swan The decision by SIS follows the position for household laundry detergents, the idea adopted by the European Commission, which behind the label, presented as an educational also allows phosphate containing products to instrument, is to encourage manufacturers to apply for the recently adopted European formulate increasingly environmentally sound Ecolabel for household laundry detergents. products. Today, 84 % of the Swedish

consumers favour Swan-labelled products.

2 SCIENT! FIC COMMITTEE ON PHOSPHATES SCOPE NEWSLETTER

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The first version of the Nordic label excluded consumption in municipal sewage ali phosphate containing detergents. Back in treatment plant " 1992, this decision had provoked reactions fr om water treatment authorities and This statement was made in a report associations like the Swedish Nature published by VA-FOR SK, a research Conservation Society, which disagreed with programme managed by VAV, the the exclusion of phosphates. Swedish Water Association. The report is entitled: Laundry detergents: Effects

The Swan label applies to products sold in on waste water treatment and the Finland, lceland, Norway and Sweden. environment,

Water samples from 27 household laundry Eco-/abe/ling of detergents for textiles, Criteria detergents were tested in order to evaluate document 1992103194 - 1999104104, Version the chemical parameters and the toxicity of 3, SIS Miljomarkning, SIS-Standardiseringen each product. The detergents were divided i Sverige, P. O. Box 3295, S-1 03 66" into 3 groups, depending on the builder Stockholm., Sweden. system used :

- phosphate based powder detergents, - phosphate-free powder detergents, SWEDEN - liquid detergents without phosphates.

SWEDI SH WATER TREATMENT The study cornes to the following conclusions: EXPERT S COMPARE PHO SPH AT& BASED AND PHO SPHATE-FREE PRODUCT S Suspended solids

The concentration of suspended solids is on average 10 times higher in the effluents of "T he use of phosphate based phosphate-free products than in phosphate detergents means lower organlc based detergents (see fig. 1 ). The use of loading, lower ecotoxicity to micro phosphate substitutes leads to the production organisms, lower concentration of of larger amounts of sewage sludge, which suspended solids and a lower oxygen

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Association Sans But Lucratif must be disposed of by incineration or in free powders are used instead of phosphate landfill sites. based powders. The Biological Oxygen Oemand (BOO) is six times higher when 1500 phosphate-free liquid detergents are used (see fig. 3). 1000 1--

1000

!--- !--- 500 800

600 � hfffL fi l"i n 1-:i t" 0 PBD PFP PFL 400 fig. 1 : Suspended solids (mg/1) ln contrast, phosphate is the only detergent 200 � builder which can be recovered in sewage 0 PBD PFP PFL plants and recycled, therefore increasing the fig. 2: Total Organic carbon (mg/1) possible exploitation of this resource. On the other hand, the use of phosphate leads to 3000 larger consumption of flocculating agents in "' sewage treatment, when enhanced biological 2500 treatment is not applied. 2000 1500 ""�"'l"' l"' 1000 Concentration of organic material and 500 � rrrrn 1 � ecotoxicity 0 1 --· PBP PFP PFL fig. 3 : Biological Oxygen Demand (mg/1)

Phosphate based detergents produce the effluent with the lowest concentration of organic material (measured in TOC (see fig. The ecotoxicity towards micro-organisms 2) and OOC1). The release of organic generally follows the content of organic material leads to a consumption of oxygen carbon (TOC). Therefore, there are large (BOO) in the effluent from the washing differences between the detergents tested. machine three times higher when phosphate- Liquid detergents without phosphates appear to have the highest potential impact, with l TOC and DOC stand for Total Organic Carbon and Dissolved Organic Carbon. respect to this parameter (see fig. 4). 4 SCIENT! FIC COMMIITEE ON PHOSPHATES SCOPE NEWSLETTER

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500 909 770 Cajsa Wahlberg, VAV- VA-Forsk, Tvattmedel 400 - effecter pa reningsverk och mi/jo, Stockholm 1995. 300 1- Vatten,

200 ,. - - 100 ..,.. �.mm fi ., 1 0 Fi PSP 1 LSP UNITED KINGDOM fig. 4 : Ecotoxicity (measured according to the microtox method) LC50 (15 min.) PHOSPHATES USED TO RESTORE ACIDIFIED LAKES

No long term environmental impact

Tests conducted by researchers at the The report notes "that most ecolabeled lnstitute of Freshwater Ecology and products are easily degradable". Among the Lancaster University reve_al that products tested, none or very little ecotoxicity phosphates can be used to control could be detected after 14 days of lake acidity. degradation, with the exception of one product which is no longer on the market. A series of tests were conducted from 1992 to 1993 in Seathwaite tarn, in Northern England The potential ecotoxicity will rapidly disappear Lake District, in order to determine the ability as the surfactant degrades, and the risk of any of. phosphate fertilisation to control lake long term environmental effects will be acidity. Many lakes are dramatically acidified eliminated, says the report. by airborne pollutants generated by combustion from industrial and transportation The study was conducted assuming that activities. advanced waste water treatment is implemented. Therefore, no assessment is The traditionnal approach to lake acidification made of the possible environmental impact of consists of adding lime to lower the pH value ecotoxicity, when sewage water is discharged of the water. This technique, however, tends directly into the natural environment. to provoke a modification of the plant and animal communities naturally present in the lakes. The original species are often unable to

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Association Sans But Lucratif cope with the excessive concentration of The authors conclude that "phosphate can calcium and are rapidly replaced by more have beneficiai effects within the environment, tolerant species, thus modifying the natural and that the complete elimination may composition of the ecosystems. enhance problems of low productivity and acidity. The idea of using phosphates to control lake acidity is supported by the tact that W. Davison , O. G. George & N. J. A. Edwards, phytoplankton productivity can act as an Contra/led reversai of lake acidifcation by important butter of soft water. The treatment with phosphate fertilizer, in Nature, phytoplankton feeds on nitrate ions which are vol. 317, october 1995. largely responsible for lake acidity.

The experiment showed that the phosphorus

added to the lake in the form of fertiliser is FRANCE & SWITZERLAND rapidly assimilated by growing phytoplankton.

For each mole of phosphate, 16 moles of EVOLUTION OF PHOSPHORUS AND nitrate nitrogen are consumed. This ratio BIOMASS CONCENTRATION IN LAKE illustrates that very low quantities of fertiliser GENEVA. are needed to obtain satisfactory results in terms of pH increase without affecting the community structure.

8o th ph o sphorus and biomass The corresponding increase of phytoplankton concentrations decreased in 1994. chlorophyll was due to " the rapid growth of Biomass concentration still remains small species that are commonly referred to higher than values recorded from 1989 as nano-plankton". to 1991. The International Commission for the Protection of the Leman Waters ln turn, "these species are consumed in large (CIPEL) announces that 87 o/o of the numbers by tiller-feeding crustacean which population of the lake's catchment greatly accelerate the rate at which the fixed area is now connected to waste water carbon is deposited in fixed sediments. treatment plants.

6 SCIENTIFIC COMMITTEE ON PHOSPHATES SCOPE NEWSLETTER

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Phosphorus content of the Lake has regularly - the closing or modification of pig farms, decreased since 1981, to reach a 45 - the increase of storage facilities for micrograms per litre concentration. manure produced by cattle farms. Meanwhile, however, the biomass concentration has not followed a regular The changes observed in the lake decreasing curve. phytoplankton show that eutrophication and related negative effects are diminishing. This As of in 1989, the biomass stopped evolution, however is still considered decreasing. lnstead, the period from 1989 to insufficient. 1993 showed an unexpected increase of phytoplankton density. During the latest year 1994 primary productivity is regarded as quite low. The very low value registered during the of observations, biomass had decreased spring is thought to be due to a very short again but was still higher than the lowest period of sunshine. value reached in 1989.

ln the light of this data, it is difficult to define Rapport sur les études et recherches whether the evolution of the biomass during entreprises dans Je bassin lémanique, the last year is part of a decreasing trend, or if Campagne 1994, Consei l Scientifique de la it must be considered as an exception in a Commission Internationale pour la Protection general stabilisation of the Lake's des Eaux du Léman, 1995. phytoplankton density.

The regular decrease in phosphorus concentration is the result of an extensive phosphorus control programme. This programme includes:

-the installation of waste water treatment for almost the entire population surrounding the lake (85%), - the control of phosphorus release by industries,

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Association Sans But Lucratif ..

The SCOPE Newsletter ls produced by the SCIENTIFIC COMMITTEE ON PHOSPHATES IN EUROPE, a non commercial, non profit­ making association (Association Sans But Lucratif) based in Brussels.

The association lncludes International groups headquartered ln Belgium, France, Spain, Sweden and the UK, producers of a wide variety of detergent ingredients including phosphates. lts aim ls to provlde a platform for objective and scientific information on the effects of phosphate-containing and phosphate-freedetergents on the environment.

The SCOPE Newsletter ls open to input from its readers across Europe and we welcome ali comments or information. Contributions from readers are invited on ali subjects conceming phosphates, detergents, sewagetreatment and the environment. You are invited to submit scientific papers for résumé, to send comments on the studies mentioned in this Newsletter or other scientific or technical news.

For each study or paper mentioned in the SCOPE Newsletter, the full document can be obtained directly from :

E.C.U. (European Communications Unit)- who produce this Newsletter for SCOPE- 81, rue François Mermet- 69160TASSIN France- Tél : (33) 78.M.23.39- Fax L(33)78. 34. 83. 49

If you want the SCOPE NEWSLETTER to be distribued to other contacts

D New contact D Address correction D Back numbers order

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